diff --git a/core/config/engine.cpp b/core/config/engine.cpp
index d9abf5e5e998..5b5ec7323b3b 100644
--- a/core/config/engine.cpp
+++ b/core/config/engine.cpp
@@ -31,10 +31,15 @@
 #include "engine.h"
 
 #include "core/authors.gen.h"
-#include "core/config/project_settings.h"
 #include "core/donors.gen.h"
+#include "core/error/error_macros.h"
 #include "core/license.gen.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/print_string.h"
+#include "core/variant/variant.h"
 #include "core/version.h"
+#include "core/version_generated.gen.h"
 #include "core/version_hash.gen.h"
 
 void Engine::set_physics_ticks_per_second(int p_ips) {
diff --git a/core/config/engine.h b/core/config/engine.h
index 65ca58ba1a8f..56a97f893cc8 100644
--- a/core/config/engine.h
+++ b/core/config/engine.h
@@ -31,10 +31,19 @@
 #ifndef ENGINE_H
 #define ENGINE_H
 
+#include <stdint.h>
+
 #include "core/os/main_loop.h"
+#include "core/string/string_name.h"
 #include "core/string/ustring.h"
 #include "core/templates/list.h"
+#include "core/templates/map.h"
 #include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
+
+class Object;
 
 class Engine {
 public:
diff --git a/core/config/project_settings.cpp b/core/config/project_settings.cpp
index b5f1015ff537..6b37624eede2 100644
--- a/core/config/project_settings.cpp
+++ b/core/config/project_settings.cpp
@@ -30,20 +30,27 @@
 
 #include "project_settings.h"
 
-#include "core/core_bind.h" // For Compression enum.
+#include "core/config/engine.h"
 #include "core/core_string_names.h"
+#include "core/error/error_macros.h"
+#include "core/input/input_event.h"
 #include "core/input/input_map.h"
+#include "core/io/compression.h"
 #include "core/io/dir_access.h"
 #include "core/io/file_access.h"
 #include "core/io/file_access_network.h"
 #include "core/io/file_access_pack.h"
 #include "core/io/marshalls.h"
-#include "core/os/keyboard.h"
+#include "core/object/class_db.h"
+#include "core/object/ref_counted.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/templates/pair.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
 #include "core/variant/variant_parser.h"
 #include "core/version.h"
-
-#include "modules/modules_enabled.gen.h" // For mono.
+#include "core/version_generated.gen.h"
 
 const String ProjectSettings::PROJECT_DATA_DIR_NAME_SUFFIX = "godot";
 
diff --git a/core/config/project_settings.h b/core/config/project_settings.h
index 614a11f7262b..b1f95eedbad6 100644
--- a/core/config/project_settings.h
+++ b/core/config/project_settings.h
@@ -31,10 +31,23 @@
 #ifndef PROJECT_SETTINGS_H
 #define PROJECT_SETTINGS_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/object/class_db.h"
+#include "core/object/object.h"
 #include "core/os/thread_safe.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
 #include "core/templates/ordered_hash_map.h"
 #include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
+
+class Dictionary;
 
 class ProjectSettings : public Object {
 	GDCLASS(ProjectSettings, Object);
diff --git a/core/core_bind.cpp b/core/core_bind.cpp
index 8d03f35617f9..ed340876d8f7 100644
--- a/core/core_bind.cpp
+++ b/core/core_bind.cpp
@@ -30,16 +30,38 @@
 
 #include "core_bind.h"
 
+#include <stddef.h>
+#include <initializer_list>
+
+#include "core/config/engine.h"
 #include "core/config/project_settings.h"
 #include "core/crypto/crypto_core.h"
 #include "core/debugger/engine_debugger.h"
+#include "core/error/error_macros.h"
+#include "core/io/dir_access.h"
+#include "core/io/file_access.h"
 #include "core/io/file_access_compressed.h"
 #include "core/io/file_access_encrypted.h"
+#include "core/io/image.h"
 #include "core/io/marshalls.h"
+#include "core/io/resource_loader.h"
+#include "core/io/resource_saver.h"
 #include "core/math/geometry_2d.h"
 #include "core/math/geometry_3d.h"
+#include "core/math/vector2i.h"
+#include "core/object/class_db.h"
+#include "core/object/method_bind.h"
+#include "core/object/object_id.h"
+#include "core/object/script_language.h"
 #include "core/os/keyboard.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/string/print_string.h"
+#include "core/templates/list.h"
+#include "core/templates/pair.h"
+#include "core/typedefs.h"
+
+struct Plane;
 
 namespace core_bind {
 
diff --git a/core/core_bind.h b/core/core_bind.h
index ac0e92a87ab1..55381b8aff77 100644
--- a/core/core_bind.h
+++ b/core/core_bind.h
@@ -31,18 +31,42 @@
 #ifndef CORE_BIND_H
 #define CORE_BIND_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/compression.h"
 #include "core/io/dir_access.h"
 #include "core/io/file_access.h"
 #include "core/io/image.h"
+#include "core/io/resource.h"
 #include "core/io/resource_loader.h"
 #include "core/io/resource_saver.h"
+#include "core/io/resource_uid.h"
+#include "core/math/math_defs.h"
+#include "core/math/vector2.h"
+#include "core/math/vector3.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/os/keyboard.h"
+#include "core/os/mutex.h"
 #include "core/os/os.h"
 #include "core/os/semaphore.h"
 #include "core/os/thread.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/map.h"
 #include "core/templates/safe_refcount.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/variant.h"
 
 class MainLoop;
+class DirAccess;
+class FileAccess;
+struct Plane;
 
 namespace core_bind {
 
diff --git a/core/core_constants.cpp b/core/core_constants.cpp
index 2f5fd05e6acc..5bf00df1d271 100644
--- a/core/core_constants.cpp
+++ b/core/core_constants.cpp
@@ -30,10 +30,16 @@
 
 #include "core_constants.h"
 
-#include "core/input/input_event.h"
+#include "core/error/error_list.h"
+#include "core/input/input_enums.h"
+#include "core/math/math_defs.h"
 #include "core/multiplayer/multiplayer.h"
-#include "core/object/class_db.h"
+#include "core/object/method_bind.h"
+#include "core/object/object.h"
 #include "core/os/keyboard.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/type_info.h"
 #include "core/variant/variant.h"
 
 struct _CoreConstant {
diff --git a/core/core_string_names.h b/core/core_string_names.h
index 2cd4e335b27f..c4306db798c7 100644
--- a/core/core_string_names.h
+++ b/core/core_string_names.h
@@ -31,7 +31,9 @@
 #ifndef CORE_STRING_NAMES_H
 #define CORE_STRING_NAMES_H
 
+#include "core/os/memory.h"
 #include "core/string/string_name.h"
+#include "core/typedefs.h"
 
 class CoreStringNames {
 	friend void register_core_types();
diff --git a/core/crypto/aes_context.cpp b/core/crypto/aes_context.cpp
index 8ff4f6a34ca0..947449785d03 100644
--- a/core/crypto/aes_context.cpp
+++ b/core/crypto/aes_context.cpp
@@ -30,6 +30,11 @@
 
 #include "core/crypto/aes_context.h"
 
+#include <stdint.h>
+
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
+
 Error AESContext::start(Mode p_mode, PackedByteArray p_key, PackedByteArray p_iv) {
 	ERR_FAIL_COND_V_MSG(mode != MODE_MAX, ERR_ALREADY_IN_USE, "AESContext already started. Call 'finish' before starting a new one.");
 	ERR_FAIL_COND_V_MSG(p_mode < 0 || p_mode >= MODE_MAX, ERR_INVALID_PARAMETER, "Invalid mode requested.");
diff --git a/core/crypto/aes_context.h b/core/crypto/aes_context.h
index 2121adfcc616..00e9f9c1d382 100644
--- a/core/crypto/aes_context.h
+++ b/core/crypto/aes_context.h
@@ -32,7 +32,11 @@
 #define AES_CONTEXT_H
 
 #include "core/crypto/crypto_core.h"
+#include "core/error/error_list.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/variant.h"
 
 class AESContext : public RefCounted {
 	GDCLASS(AESContext, RefCounted);
diff --git a/core/crypto/crypto.cpp b/core/crypto/crypto.cpp
index f62d2cce1fe6..d2345275b165 100644
--- a/core/crypto/crypto.cpp
+++ b/core/crypto/crypto.cpp
@@ -30,9 +30,8 @@
 
 #include "crypto.h"
 
-#include "core/config/engine.h"
-#include "core/io/certs_compressed.gen.h"
-#include "core/io/compression.h"
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
 
 /// Resources
 
diff --git a/core/crypto/crypto.h b/core/crypto/crypto.h
index 9de2c16fbc6b..ee2a5fd2e648 100644
--- a/core/crypto/crypto.h
+++ b/core/crypto/crypto.h
@@ -31,11 +31,19 @@
 #ifndef CRYPTO_H
 #define CRYPTO_H
 
+#include <stdint.h>
+
 #include "core/crypto/hashing_context.h"
+#include "core/error/error_list.h"
 #include "core/io/resource.h"
 #include "core/io/resource_loader.h"
 #include "core/io/resource_saver.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/variant/variant.h"
 
 class CryptoKey : public Resource {
 	GDCLASS(CryptoKey, Resource);
diff --git a/core/crypto/crypto_core.cpp b/core/crypto/crypto_core.cpp
index 9f000c5aebd8..012041ae2e2c 100644
--- a/core/crypto/crypto_core.cpp
+++ b/core/crypto/crypto_core.cpp
@@ -36,6 +36,9 @@
 #include <mbedtls/sha1.h>
 #include <mbedtls/sha256.h>
 
+#include "core/os/memory.h"
+#include "core/templates/vector.h"
+
 // MD5
 CryptoCore::MD5Context::MD5Context() {
 	ctx = memalloc(sizeof(mbedtls_md5_context));
diff --git a/core/crypto/crypto_core.h b/core/crypto/crypto_core.h
index 355f4a2404bd..74d21c2459c6 100644
--- a/core/crypto/crypto_core.h
+++ b/core/crypto/crypto_core.h
@@ -31,7 +31,12 @@
 #ifndef CRYPTO_CORE_H
 #define CRYPTO_CORE_H
 
+#include <stddef.h>
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
 
 class CryptoCore {
 public:
diff --git a/core/crypto/hashing_context.cpp b/core/crypto/hashing_context.cpp
index 2ff540f79800..c5b3dd623598 100644
--- a/core/crypto/hashing_context.cpp
+++ b/core/crypto/hashing_context.cpp
@@ -30,7 +30,13 @@
 
 #include "hashing_context.h"
 
+#include <stddef.h>
+#include <stdint.h>
+
 #include "core/crypto/crypto_core.h"
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
 
 Error HashingContext::start(HashType p_type) {
 	ERR_FAIL_COND_V(ctx != nullptr, ERR_ALREADY_IN_USE);
diff --git a/core/crypto/hashing_context.h b/core/crypto/hashing_context.h
index 1a7cabf0f1ee..8ac42c9ddff6 100644
--- a/core/crypto/hashing_context.h
+++ b/core/crypto/hashing_context.h
@@ -31,7 +31,11 @@
 #ifndef HASHING_CONTEXT_H
 #define HASHING_CONTEXT_H
 
+#include "core/error/error_list.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/variant.h"
 
 class HashingContext : public RefCounted {
 	GDCLASS(HashingContext, RefCounted);
diff --git a/core/debugger/debugger_marshalls.cpp b/core/debugger/debugger_marshalls.cpp
index 1a746d59a3f4..db1347b35d7a 100644
--- a/core/debugger/debugger_marshalls.cpp
+++ b/core/debugger/debugger_marshalls.cpp
@@ -30,6 +30,8 @@
 
 #include "debugger_marshalls.h"
 
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
 #include "core/io/marshalls.h"
 
 #define CHECK_SIZE(arr, expected, what) ERR_FAIL_COND_V_MSG((uint32_t)arr.size() < (uint32_t)(expected), false, String("Malformed ") + what + " message from script debugger, message too short. Expected size: " + itos(expected) + ", actual size: " + itos(arr.size()))
diff --git a/core/debugger/debugger_marshalls.h b/core/debugger/debugger_marshalls.h
index fae766812a07..870294f6337d 100644
--- a/core/debugger/debugger_marshalls.h
+++ b/core/debugger/debugger_marshalls.h
@@ -31,7 +31,17 @@
 #ifndef DEBUGGER_MARSHARLLS_H
 #define DEBUGGER_MARSHARLLS_H
 
+#include <stdint.h>
+
+#include "core/object/object_id.h"
 #include "core/object/script_language.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/rid.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
+#include "core/variant/variant.h"
 #include "servers/rendering_server.h"
 
 struct DebuggerMarshalls {
diff --git a/core/debugger/engine_debugger.cpp b/core/debugger/engine_debugger.cpp
index 54760d8d65dd..da2499da21e3 100644
--- a/core/debugger/engine_debugger.cpp
+++ b/core/debugger/engine_debugger.cpp
@@ -34,7 +34,11 @@
 #include "core/debugger/remote_debugger.h"
 #include "core/debugger/remote_debugger_peer.h"
 #include "core/debugger/script_debugger.h"
+#include "core/math/math_defs.h"
+#include "core/object/ref_counted.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/templates/pair.h"
 
 EngineDebugger *EngineDebugger::singleton = nullptr;
 ScriptDebugger *EngineDebugger::script_debugger = nullptr;
diff --git a/core/debugger/engine_debugger.h b/core/debugger/engine_debugger.h
index fdfa41c9ccf6..3a24c9be22a1 100644
--- a/core/debugger/engine_debugger.h
+++ b/core/debugger/engine_debugger.h
@@ -31,10 +31,15 @@
 #ifndef ENGINE_DEBUGGER_H
 #define ENGINE_DEBUGGER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
 #include "core/string/string_name.h"
 #include "core/string/ustring.h"
 #include "core/templates/map.h"
 #include "core/templates/vector.h"
+#include "core/typedefs.h"
 #include "core/variant/array.h"
 #include "core/variant/variant.h"
 
diff --git a/core/debugger/local_debugger.cpp b/core/debugger/local_debugger.cpp
index 61d75a6a0d19..6e12c43c00d8 100644
--- a/core/debugger/local_debugger.cpp
+++ b/core/debugger/local_debugger.cpp
@@ -30,10 +30,24 @@
 
 #include "local_debugger.h"
 
+#include <stdint.h>
+
 #include "core/debugger/script_debugger.h"
+#include "core/math/math_defs.h"
+#include "core/object/script_language.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/string/print_string.h"
+#include "core/string/string_name.h"
+#include "core/templates/set.h"
+#include "core/templates/sort_array.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
 #include "scene/main/scene_tree.h"
 
+class Array;
+
 struct LocalDebugger::ScriptsProfiler {
 	struct ProfileInfoSort {
 		bool operator()(const ScriptLanguage::ProfilingInfo &A, const ScriptLanguage::ProfilingInfo &B) const {
diff --git a/core/debugger/local_debugger.h b/core/debugger/local_debugger.h
index ecd805a6cb37..64f081dea3ea 100644
--- a/core/debugger/local_debugger.h
+++ b/core/debugger/local_debugger.h
@@ -32,8 +32,15 @@
 #define LOCAL_DEBUGGER_H
 
 #include "core/debugger/engine_debugger.h"
+#include "core/error/error_macros.h"
 #include "core/object/script_language.h"
+#include "core/string/ustring.h"
 #include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/pair.h"
+
+class Array;
+class Variant;
 
 class LocalDebugger : public EngineDebugger {
 private:
diff --git a/core/debugger/remote_debugger.cpp b/core/debugger/remote_debugger.cpp
index 339aa9b61f59..443e332087e2 100644
--- a/core/debugger/remote_debugger.cpp
+++ b/core/debugger/remote_debugger.cpp
@@ -30,15 +30,34 @@
 
 #include "remote_debugger.h"
 
+#include <stdint.h>
+
+#include "core/config/engine.h"
 #include "core/config/project_settings.h"
 #include "core/debugger/debugger_marshalls.h"
 #include "core/debugger/engine_debugger.h"
 #include "core/debugger/script_debugger.h"
 #include "core/input/input.h"
+#include "core/io/image.h"
+#include "core/math/math_defs.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
 #include "core/object/script_language.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/templates/map.h"
+#include "core/templates/pair.h"
+#include "core/templates/rid.h"
+#include "core/templates/sort_array.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/variant.h"
 #include "scene/main/node.h"
 #include "servers/display_server.h"
+#include "servers/rendering_server.h"
 
 template <typename T>
 void RemoteDebugger::_bind_profiler(const String &p_name, T *p_prof) {
diff --git a/core/debugger/remote_debugger.h b/core/debugger/remote_debugger.h
index bd64955c8922..3f72d0312dd6 100644
--- a/core/debugger/remote_debugger.h
+++ b/core/debugger/remote_debugger.h
@@ -34,11 +34,21 @@
 #include "core/debugger/debugger_marshalls.h"
 #include "core/debugger/engine_debugger.h"
 #include "core/debugger/remote_debugger_peer.h"
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
 #include "core/object/class_db.h"
+#include "core/object/ref_counted.h"
+#include "core/os/mutex.h"
+#include "core/os/thread.h"
+#include "core/string/print_string.h"
 #include "core/string/string_name.h"
 #include "core/string/ustring.h"
+#include "core/templates/list.h"
 #include "core/variant/array.h"
 
+class Array;
+class Variant;
+
 class RemoteDebugger : public EngineDebugger {
 public:
 	enum MessageType {
diff --git a/core/debugger/remote_debugger_peer.cpp b/core/debugger/remote_debugger_peer.cpp
index 7c7d38ab0a8a..1eedd2840754 100644
--- a/core/debugger/remote_debugger_peer.cpp
+++ b/core/debugger/remote_debugger_peer.cpp
@@ -31,8 +31,15 @@
 #include "remote_debugger_peer.h"
 
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
+#include "core/io/ip.h"
+#include "core/io/ip_address.h"
 #include "core/io/marshalls.h"
+#include "core/io/net_socket.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/string/print_string.h"
+#include "core/variant/variant.h"
 
 bool RemoteDebuggerPeerTCP::is_peer_connected() {
 	return connected;
diff --git a/core/debugger/remote_debugger_peer.h b/core/debugger/remote_debugger_peer.h
index 010336ffd349..62eadb12418c 100644
--- a/core/debugger/remote_debugger_peer.h
+++ b/core/debugger/remote_debugger_peer.h
@@ -31,11 +31,17 @@
 #ifndef REMOTE_DEBUGGER_PEER_H
 #define REMOTE_DEBUGGER_PEER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/stream_peer_tcp.h"
 #include "core/object/ref_counted.h"
 #include "core/os/mutex.h"
 #include "core/os/thread.h"
 #include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
 
 class RemoteDebuggerPeer : public RefCounted {
 protected:
diff --git a/core/debugger/script_debugger.cpp b/core/debugger/script_debugger.cpp
index 4dd93249ef7d..6c71e1d1ec73 100644
--- a/core/debugger/script_debugger.cpp
+++ b/core/debugger/script_debugger.cpp
@@ -31,6 +31,7 @@
 #include "script_debugger.h"
 
 #include "core/debugger/engine_debugger.h"
+#include "core/typedefs.h"
 
 void ScriptDebugger::set_lines_left(int p_left) {
 	lines_left = p_left;
diff --git a/core/debugger/script_debugger.h b/core/debugger/script_debugger.h
index feb6702b54f9..b58860ad409b 100644
--- a/core/debugger/script_debugger.h
+++ b/core/debugger/script_debugger.h
@@ -31,8 +31,10 @@
 #ifndef SCRIPT_DEBUGGER_H
 #define SCRIPT_DEBUGGER_H
 
+#include "core/error/error_macros.h"
 #include "core/object/script_language.h"
 #include "core/string/string_name.h"
+#include "core/string/ustring.h"
 #include "core/templates/map.h"
 #include "core/templates/set.h"
 #include "core/templates/vector.h"
diff --git a/core/doc_data.cpp b/core/doc_data.cpp
index 1e72ad109039..c190e9eea33d 100644
--- a/core/doc_data.cpp
+++ b/core/doc_data.cpp
@@ -30,6 +30,8 @@
 
 #include "doc_data.h"
 
+#include "core/templates/list.h"
+
 void DocData::return_doc_from_retinfo(DocData::MethodDoc &p_method, const PropertyInfo &p_retinfo) {
 	if (p_retinfo.type == Variant::INT && p_retinfo.hint == PROPERTY_HINT_INT_IS_POINTER) {
 		p_method.return_type = p_retinfo.hint_string;
diff --git a/core/doc_data.h b/core/doc_data.h
index 9286b843beac..c32c9dd886ca 100644
--- a/core/doc_data.h
+++ b/core/doc_data.h
@@ -32,7 +32,11 @@
 #define DOC_DATA_H
 
 #include "core/io/xml_parser.h"
+#include "core/object/object.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
 #include "core/templates/map.h"
+#include "core/templates/vector.h"
 #include "core/variant/variant.h"
 
 struct ScriptMemberInfo {
diff --git a/core/error/error_macros.cpp b/core/error/error_macros.cpp
index ceccd43259b0..cbc3cad36596 100644
--- a/core/error/error_macros.cpp
+++ b/core/error/error_macros.cpp
@@ -30,6 +30,8 @@
 
 #include "error_macros.h"
 
+#include <stdio.h>
+
 #include "core/io/logger.h"
 #include "core/os/os.h"
 #include "core/string/ustring.h"
diff --git a/core/error/error_macros.h b/core/error/error_macros.h
index 7b032fb4cdf4..096c8e5a17d3 100644
--- a/core/error/error_macros.h
+++ b/core/error/error_macros.h
@@ -31,9 +31,10 @@
 #ifndef ERROR_MACROS_H
 #define ERROR_MACROS_H
 
-#include "core/typedefs.h"
+#include <stdint.h>
 
 #include "core/templates/safe_refcount.h"
+#include "core/typedefs.h"
 
 class String;
 
diff --git a/core/extension/extension_api_dump.cpp b/core/extension/extension_api_dump.cpp
index 3687e4f7e5ad..d008ce131d86 100644
--- a/core/extension/extension_api_dump.cpp
+++ b/core/extension/extension_api_dump.cpp
@@ -29,12 +29,44 @@
 /*************************************************************************/
 
 #include "extension_api_dump.h"
+
+#include <stdint.h>
+
 #include "core/config/engine.h"
 #include "core/core_constants.h"
+#include "core/extension/gdnative_interface.h"
 #include "core/io/file_access.h"
 #include "core/io/json.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
+#include "core/object/class_db.h"
+#include "core/object/method_bind.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
 #include "core/templates/pair.h"
+#include "core/templates/rid.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/callable.h"
+#include "core/variant/variant.h"
 #include "core/version.h"
+#include "core/version_generated.gen.h"
 
 #ifdef TOOLS_ENABLED
 
diff --git a/core/extension/extension_api_dump.h b/core/extension/extension_api_dump.h
index 7346e182f1b8..4f9840fa43c4 100644
--- a/core/extension/extension_api_dump.h
+++ b/core/extension/extension_api_dump.h
@@ -32,6 +32,8 @@
 #define API_DUMP_H
 
 #include "core/extension/native_extension.h"
+#include "core/string/ustring.h"
+#include "core/variant/dictionary.h"
 
 #ifdef TOOLS_ENABLED
 
diff --git a/core/extension/gdnative_interface.cpp b/core/extension/gdnative_interface.cpp
index 385117eed1f6..dd353f17b2d9 100644
--- a/core/extension/gdnative_interface.cpp
+++ b/core/extension/gdnative_interface.cpp
@@ -31,10 +31,38 @@
 #include "gdnative_interface.h"
 
 #include "core/config/engine.h"
+#include "core/error/error_macros.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
 #include "core/object/class_db.h"
+#include "core/object/method_bind.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
 #include "core/os/memory.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/hash_map.h"
+#include "core/templates/rid.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
 #include "core/variant/variant.h"
+#include "core/variant/variant_internal.h"
 #include "core/version.h"
+#include "core/version_generated.gen.h"
 
 // Memory Functions
 static void *gdnative_alloc(size_t p_size) {
diff --git a/core/extension/native_extension.cpp b/core/extension/native_extension.cpp
index 1512852234ec..8077df48d4ec 100644
--- a/core/extension/native_extension.cpp
+++ b/core/extension/native_extension.cpp
@@ -29,11 +29,20 @@
 /*************************************************************************/
 
 #include "native_extension.h"
+
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/io/config_file.h"
 #include "core/object/class_db.h"
 #include "core/object/method_bind.h"
+#include "core/object/ref_counted.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/callable.h"
+#include "core/variant/type_info.h"
+#include "core/variant/variant.h"
 
 String NativeExtension::get_extension_list_config_file() {
 	return ProjectSettings::get_singleton()->get_project_data_path().plus_file("extension_list.cfg");
diff --git a/core/extension/native_extension.h b/core/extension/native_extension.h
index b98e4925d2e1..a14bd67f6429 100644
--- a/core/extension/native_extension.h
+++ b/core/extension/native_extension.h
@@ -31,9 +31,19 @@
 #ifndef NATIVE_EXTENSION_H
 #define NATIVE_EXTENSION_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/extension/gdnative_interface.h"
+#include "core/io/resource.h"
 #include "core/io/resource_loader.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/variant/binder_common.h"
 
 class NativeExtension : public Resource {
 	GDCLASS(NativeExtension, Resource)
diff --git a/core/extension/native_extension_manager.cpp b/core/extension/native_extension_manager.cpp
index 87737858a834..78a2737186c0 100644
--- a/core/extension/native_extension_manager.cpp
+++ b/core/extension/native_extension_manager.cpp
@@ -29,7 +29,13 @@
 /*************************************************************************/
 
 #include "native_extension_manager.h"
+
+#include "core/error/error_macros.h"
 #include "core/io/file_access.h"
+#include "core/io/resource_loader.h"
+#include "core/object/class_db.h"
+#include "core/templates/pair.h"
+#include "core/typedefs.h"
 
 NativeExtensionManager::LoadStatus NativeExtensionManager::load_extension(const String &p_path) {
 	if (native_extension_map.has(p_path)) {
diff --git a/core/extension/native_extension_manager.h b/core/extension/native_extension_manager.h
index b8339e481737..897f043809a2 100644
--- a/core/extension/native_extension_manager.h
+++ b/core/extension/native_extension_manager.h
@@ -31,7 +31,15 @@
 #ifndef NATIVE_EXTENSION_MANAGER_H
 #define NATIVE_EXTENSION_MANAGER_H
 
+#include <stdint.h>
+
 #include "core/extension/native_extension.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/map.h"
+#include "core/templates/vector.h"
+#include "core/variant/binder_common.h"
 
 class NativeExtensionManager : public Object {
 	GDCLASS(NativeExtensionManager, Object);
diff --git a/core/input/input.cpp b/core/input/input.cpp
index d36d0f4da0c6..2bdda63b810d 100644
--- a/core/input/input.cpp
+++ b/core/input/input.cpp
@@ -30,10 +30,19 @@
 
 #include "input.h"
 
+#include "core/config/engine.h"
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/input/default_controller_mappings.h"
 #include "core/input/input_map.h"
+#include "core/math/math_funcs.h"
+#include "core/math/rect2.h"
+#include "core/object/class_db.h"
 #include "core/os/os.h"
+#include "core/templates/ordered_hash_map.h"
+#include "core/templates/pair.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
 
 static const char *_joy_buttons[(size_t)JoyButton::SDL_MAX] = {
 	"a",
diff --git a/core/input/input.h b/core/input/input.h
index ab2cd377f40c..ce250ad06ee1 100644
--- a/core/input/input.h
+++ b/core/input/input.h
@@ -31,10 +31,29 @@
 #ifndef INPUT_H
 #define INPUT_H
 
+#include <stddef.h>
+#include <stdint.h>
+
+#include "core/input/input_enums.h"
 #include "core/input/input_event.h"
+#include "core/io/resource.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
 #include "core/object/object.h"
+#include "core/object/ref_counted.h"
 #include "core/os/keyboard.h"
 #include "core/os/thread_safe.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
+#include "core/variant/binder_common.h"
+
+struct Rect2;
 
 class Input : public Object {
 	GDCLASS(Input, Object);
diff --git a/core/input/input_event.cpp b/core/input/input_event.cpp
index ab0f36132f14..0b2705a3000f 100644
--- a/core/input/input_event.cpp
+++ b/core/input/input_event.cpp
@@ -30,9 +30,18 @@
 
 #include "input_event.h"
 
+#include <stddef.h>
+
+#include "core/error/error_macros.h"
 #include "core/input/input_map.h"
 #include "core/input/shortcut.h"
+#include "core/math/math_funcs.h"
+#include "core/math/transform_2d.h"
+#include "core/object/class_db.h"
 #include "core/os/keyboard.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
 
 const int InputEvent::DEVICE_ID_TOUCH_MOUSE = -1;
 const int InputEvent::DEVICE_ID_INTERNAL = -2;
diff --git a/core/input/input_event.h b/core/input/input_event.h
index 114db4662322..e2186eb8bfd6 100644
--- a/core/input/input_event.h
+++ b/core/input/input_event.h
@@ -31,13 +31,22 @@
 #ifndef INPUT_EVENT_H
 #define INPUT_EVENT_H
 
+#include <stdint.h>
+
 #include "core/input/input_enums.h"
 #include "core/io/resource.h"
+#include "core/math/math_defs.h"
 #include "core/math/transform_2d.h"
+#include "core/math/vector2.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
 #include "core/os/keyboard.h"
+#include "core/string/string_name.h"
 #include "core/string/ustring.h"
 #include "core/typedefs.h"
 
+struct Transform2D;
+
 /**
  * Input Event classes. These are used in the main loop.
  * The events are pretty obvious.
diff --git a/core/input/input_map.cpp b/core/input/input_map.cpp
index 41083b4c4734..d74e56a31573 100644
--- a/core/input/input_map.cpp
+++ b/core/input/input_map.cpp
@@ -31,9 +31,16 @@
 #include "input_map.h"
 
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/input/input.h"
+#include "core/input/input_enums.h"
+#include "core/object/class_db.h"
 #include "core/os/keyboard.h"
 #include "core/os/os.h"
+#include "core/templates/map.h"
+#include "core/templates/vector.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/variant.h"
 
 InputMap *InputMap::singleton = nullptr;
 
diff --git a/core/input/input_map.h b/core/input/input_map.h
index 79b4d1038fc3..1c5d94c1e5cf 100644
--- a/core/input/input_map.h
+++ b/core/input/input_map.h
@@ -34,7 +34,13 @@
 #include "core/input/input_event.h"
 #include "core/object/class_db.h"
 #include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
 #include "core/templates/ordered_hash_map.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
 
 class InputMap : public Object {
 	GDCLASS(InputMap, Object);
diff --git a/core/input/shortcut.cpp b/core/input/shortcut.cpp
index 9eeeb449bab6..70a1f6e1d24f 100644
--- a/core/input/shortcut.cpp
+++ b/core/input/shortcut.cpp
@@ -29,7 +29,11 @@
 /*************************************************************************/
 
 #include "shortcut.h"
-#include "core/os/keyboard.h"
+
+#include "core/error/error_macros.h"
+#include "core/input/input_event.h"
+#include "core/object/class_db.h"
+#include "core/variant/variant.h"
 
 void Shortcut::set_events(const Array &p_events) {
 	for (int i = 0; i < p_events.size(); i++) {
diff --git a/core/input/shortcut.h b/core/input/shortcut.h
index 0c9689cdcb3e..c2d20143bffc 100644
--- a/core/input/shortcut.h
+++ b/core/input/shortcut.h
@@ -33,6 +33,13 @@
 
 #include "core/input/input_event.h"
 #include "core/io/resource.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/variant/array.h"
+
+class InputEvent;
 
 class Shortcut : public Resource {
 	GDCLASS(Shortcut, Resource);
diff --git a/core/io/compression.cpp b/core/io/compression.cpp
index ae5ccf8354b4..92f748ce0235 100644
--- a/core/io/compression.cpp
+++ b/core/io/compression.cpp
@@ -30,14 +30,16 @@
 
 #include "compression.h"
 
-#include "core/config/project_settings.h"
-#include "core/io/zip_io.h"
-
-#include "thirdparty/misc/fastlz.h"
-
+#include <string.h>
 #include <zlib.h>
 #include <zstd.h>
 
+#include "core/error/error_macros.h"
+#include "core/io/zip_io.h"
+#include "core/templates/vector.h"
+#include "thirdparty/misc/fastlz.h"
+#include "zconf.h"
+
 int Compression::compress(uint8_t *p_dst, const uint8_t *p_src, int p_src_size, Mode p_mode) {
 	switch (p_mode) {
 		case MODE_FASTLZ: {
diff --git a/core/io/compression.h b/core/io/compression.h
index 2e66970a6c6b..b0b97e8de864 100644
--- a/core/io/compression.h
+++ b/core/io/compression.h
@@ -31,9 +31,14 @@
 #ifndef COMPRESSION_H
 #define COMPRESSION_H
 
+#include <stdint.h>
+
 #include "core/templates/vector.h"
 #include "core/typedefs.h"
 
+template <class T>
+class Vector;
+
 class Compression {
 public:
 	static int zlib_level;
diff --git a/core/io/config_file.cpp b/core/io/config_file.cpp
index c942b417e428..bdca91491989 100644
--- a/core/io/config_file.cpp
+++ b/core/io/config_file.cpp
@@ -30,8 +30,12 @@
 
 #include "config_file.h"
 
+#include "core/error/error_macros.h"
+#include "core/io/file_access.h"
 #include "core/io/file_access_encrypted.h"
-#include "core/os/keyboard.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/templates/map.h"
 #include "core/variant/variant_parser.h"
 
 PackedStringArray ConfigFile::_get_sections() const {
diff --git a/core/io/config_file.h b/core/io/config_file.h
index 71e9080fb783..dc2e13a438c5 100644
--- a/core/io/config_file.h
+++ b/core/io/config_file.h
@@ -31,11 +31,21 @@
 #ifndef CONFIG_FILE_H
 #define CONFIG_FILE_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
 #include "core/templates/ordered_hash_map.h"
+#include "core/templates/vector.h"
+#include "core/variant/variant.h"
 #include "core/variant/variant_parser.h"
 
+class FileAccess;
+
 class ConfigFile : public RefCounted {
 	GDCLASS(ConfigFile, RefCounted);
 
diff --git a/core/io/dir_access.cpp b/core/io/dir_access.cpp
index 86d8dea3d986..2918b093b606 100644
--- a/core/io/dir_access.cpp
+++ b/core/io/dir_access.cpp
@@ -34,6 +34,8 @@
 #include "core/io/file_access.h"
 #include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
 
 String DirAccess::_get_root_path() const {
 	switch (_access_type) {
diff --git a/core/io/dir_access.h b/core/io/dir_access.h
index 8154f5366ce2..98d278af3424 100644
--- a/core/io/dir_access.h
+++ b/core/io/dir_access.h
@@ -31,6 +31,11 @@
 #ifndef DIR_ACCESS_H
 #define DIR_ACCESS_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
+#include "core/os/memory.h"
 #include "core/string/ustring.h"
 #include "core/typedefs.h"
 
diff --git a/core/io/dtls_server.cpp b/core/io/dtls_server.cpp
index b5c44e1b64b4..f35fc6e8f636 100644
--- a/core/io/dtls_server.cpp
+++ b/core/io/dtls_server.cpp
@@ -30,8 +30,7 @@
 
 #include "dtls_server.h"
 
-#include "core/config/project_settings.h"
-#include "core/io/file_access.h"
+#include "core/object/class_db.h"
 
 DTLSServer *(*DTLSServer::_create)() = nullptr;
 bool DTLSServer::available = false;
diff --git a/core/io/dtls_server.h b/core/io/dtls_server.h
index 0c9b0149b007..257125549d18 100644
--- a/core/io/dtls_server.h
+++ b/core/io/dtls_server.h
@@ -31,8 +31,15 @@
 #ifndef DTLS_SERVER_H
 #define DTLS_SERVER_H
 
+#include "core/crypto/crypto.h"
+#include "core/error/error_list.h"
 #include "core/io/net_socket.h"
 #include "core/io/packet_peer_dtls.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+
+class PacketPeerDTLS;
+class PacketPeerUDP;
 
 class DTLSServer : public RefCounted {
 	GDCLASS(DTLSServer, RefCounted);
diff --git a/core/io/file_access.cpp b/core/io/file_access.cpp
index 86836454c5bc..d920ffc7b039 100644
--- a/core/io/file_access.cpp
+++ b/core/io/file_access.cpp
@@ -32,6 +32,7 @@
 
 #include "core/config/project_settings.h"
 #include "core/crypto/crypto_core.h"
+#include "core/error/error_macros.h"
 #include "core/io/file_access_pack.h"
 #include "core/io/marshalls.h"
 #include "core/os/os.h"
diff --git a/core/io/file_access.h b/core/io/file_access.h
index 5413665440d4..f2db163f64c1 100644
--- a/core/io/file_access.h
+++ b/core/io/file_access.h
@@ -31,9 +31,13 @@
 #ifndef FILE_ACCESS_H
 #define FILE_ACCESS_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/math/math_defs.h"
 #include "core/os/memory.h"
 #include "core/string/ustring.h"
+#include "core/templates/vector.h"
 #include "core/typedefs.h"
 
 /**
diff --git a/core/io/file_access_compressed.cpp b/core/io/file_access_compressed.cpp
index 526952b14f76..f256c3ecfe9d 100644
--- a/core/io/file_access_compressed.cpp
+++ b/core/io/file_access_compressed.cpp
@@ -30,7 +30,9 @@
 
 #include "file_access_compressed.h"
 
-#include "core/string/print_string.h"
+#include "core/error/error_macros.h"
+#include "core/os/memory.h"
+#include "core/typedefs.h"
 
 void FileAccessCompressed::configure(const String &p_magic, Compression::Mode p_mode, uint32_t p_block_size) {
 	magic = p_magic.ascii().get_data();
diff --git a/core/io/file_access_compressed.h b/core/io/file_access_compressed.h
index 97ef3fbdeb07..b928f67f8e5a 100644
--- a/core/io/file_access_compressed.h
+++ b/core/io/file_access_compressed.h
@@ -31,8 +31,13 @@
 #ifndef FILE_ACCESS_COMPRESSED_H
 #define FILE_ACCESS_COMPRESSED_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/compression.h"
 #include "core/io/file_access.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
 
 class FileAccessCompressed : public FileAccess {
 	Compression::Mode cmode = Compression::MODE_ZSTD;
diff --git a/core/io/file_access_encrypted.cpp b/core/io/file_access_encrypted.cpp
index 8ee19d3d0674..37594caa6367 100644
--- a/core/io/file_access_encrypted.cpp
+++ b/core/io/file_access_encrypted.cpp
@@ -30,11 +30,13 @@
 
 #include "file_access_encrypted.h"
 
-#include "core/crypto/crypto_core.h"
-#include "core/string/print_string.h"
-#include "core/variant/variant.h"
+#include <string.h>
 
-#include <stdio.h>
+#include "core/crypto/crypto_core.h"
+#include "core/error/error_macros.h"
+#include "core/math/math_funcs.h"
+#include "core/os/memory.h"
+#include "core/typedefs.h"
 
 Error FileAccessEncrypted::open_and_parse(FileAccess *p_base, const Vector<uint8_t> &p_key, Mode p_mode, bool p_with_magic) {
 	ERR_FAIL_COND_V_MSG(file != nullptr, ERR_ALREADY_IN_USE, "Can't open file while another file from path '" + file->get_path_absolute() + "' is open.");
diff --git a/core/io/file_access_encrypted.h b/core/io/file_access_encrypted.h
index be5904c894d3..584a816dac51 100644
--- a/core/io/file_access_encrypted.h
+++ b/core/io/file_access_encrypted.h
@@ -31,7 +31,12 @@
 #ifndef FILE_ACCESS_ENCRYPTED_H
 #define FILE_ACCESS_ENCRYPTED_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
 
 #define ENCRYPTED_HEADER_MAGIC 0x43454447
 
diff --git a/core/io/file_access_memory.cpp b/core/io/file_access_memory.cpp
index 4aca26b007c7..3ced6280f3b1 100644
--- a/core/io/file_access_memory.cpp
+++ b/core/io/file_access_memory.cpp
@@ -30,9 +30,13 @@
 
 #include "file_access_memory.h"
 
+#include <string.h>
+
 #include "core/config/project_settings.h"
-#include "core/io/dir_access.h"
+#include "core/error/error_macros.h"
+#include "core/os/memory.h"
 #include "core/templates/map.h"
+#include "core/typedefs.h"
 
 static Map<String, Vector<uint8_t>> *files = nullptr;
 
diff --git a/core/io/file_access_memory.h b/core/io/file_access_memory.h
index 50b23e1f326a..80b496099ab7 100644
--- a/core/io/file_access_memory.h
+++ b/core/io/file_access_memory.h
@@ -31,7 +31,12 @@
 #ifndef FILE_ACCESS_MEMORY_H
 #define FILE_ACCESS_MEMORY_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
 
 class FileAccessMemory : public FileAccess {
 	uint8_t *data = nullptr;
diff --git a/core/io/file_access_network.cpp b/core/io/file_access_network.cpp
index cb38ac09284c..ef5678ced86e 100644
--- a/core/io/file_access_network.cpp
+++ b/core/io/file_access_network.cpp
@@ -31,9 +31,15 @@
 #include "file_access_network.h"
 
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/io/ip.h"
+#include "core/io/ip_address.h"
 #include "core/io/marshalls.h"
+#include "core/io/stream_peer_tcp.h"
+#include "core/object/object.h"
 #include "core/os/os.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
 
 //#define DEBUG_PRINT(m_p) print_line(m_p)
 //#define DEBUG_TIME(m_what) printf("MS: %s - %lli\n",m_what,OS::get_singleton()->get_ticks_usec());
diff --git a/core/io/file_access_network.h b/core/io/file_access_network.h
index 6cae49b54004..afc0383d5f03 100644
--- a/core/io/file_access_network.h
+++ b/core/io/file_access_network.h
@@ -31,12 +31,22 @@
 #ifndef FILE_ACCESS_NETWORK_H
 #define FILE_ACCESS_NETWORK_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
 #include "core/io/stream_peer_tcp.h"
+#include "core/object/ref_counted.h"
+#include "core/os/mutex.h"
 #include "core/os/semaphore.h"
 #include "core/os/thread.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/vector.h"
 
 class FileAccessNetwork;
+class StreamPeerTCP;
 
 class FileAccessNetworkClient {
 	struct BlockRequest {
diff --git a/core/io/file_access_pack.cpp b/core/io/file_access_pack.cpp
index 7dbea96c3d6a..78d34d22daad 100644
--- a/core/io/file_access_pack.cpp
+++ b/core/io/file_access_pack.cpp
@@ -30,11 +30,11 @@
 
 #include "file_access_pack.h"
 
+#include "core/error/error_macros.h"
 #include "core/io/file_access_encrypted.h"
 #include "core/object/script_language.h"
-#include "core/version.h"
-
-#include <stdio.h>
+#include "core/templates/pair.h"
+#include "core/version_generated.gen.h"
 
 Error PackedData::add_pack(const String &p_path, bool p_replace_files, uint64_t p_offset) {
 	for (int i = 0; i < sources.size(); i++) {
diff --git a/core/io/file_access_pack.h b/core/io/file_access_pack.h
index 6eee2f593d98..48a77a0c73f1 100644
--- a/core/io/file_access_pack.h
+++ b/core/io/file_access_pack.h
@@ -31,12 +31,19 @@
 #ifndef FILE_ACCESS_PACK_H
 #define FILE_ACCESS_PACK_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/dir_access.h"
 #include "core/io/file_access.h"
+#include "core/os/memory.h"
 #include "core/string/print_string.h"
+#include "core/string/ustring.h"
 #include "core/templates/list.h"
 #include "core/templates/map.h"
 #include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
 
 // Godot's packed file magic header ("GDPC" in ASCII).
 #define PACK_HEADER_MAGIC 0x43504447
diff --git a/core/io/file_access_zip.cpp b/core/io/file_access_zip.cpp
index 634786277588..82bfe063d242 100644
--- a/core/io/file_access_zip.cpp
+++ b/core/io/file_access_zip.cpp
@@ -32,7 +32,15 @@
 
 #include "file_access_zip.h"
 
+#include <stdlib.h>
+#include <string.h>
+
+#include "core/error/error_macros.h"
 #include "core/io/file_access.h"
+#include "core/os/memory.h"
+#include "core/typedefs.h"
+#include "thirdparty/minizip/ioapi.h"
+#include "zconf.h"
 
 ZipArchive *ZipArchive::instance = nullptr;
 
diff --git a/core/io/file_access_zip.h b/core/io/file_access_zip.h
index 7cd5893101bb..aa9ce44e5de0 100644
--- a/core/io/file_access_zip.h
+++ b/core/io/file_access_zip.h
@@ -31,15 +31,20 @@
 #ifndef FILE_ACCESS_ZIP_H
 #define FILE_ACCESS_ZIP_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/io/file_access.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
 #ifdef MINIZIP_ENABLED
 
+#include <stdlib.h>
+
 #include "core/io/file_access_pack.h"
 #include "core/templates/map.h"
-
 #include "thirdparty/minizip/unzip.h"
 
-#include <stdlib.h>
-
 class ZipArchive : public PackSource {
 public:
 	struct File {
diff --git a/core/io/http_client.cpp b/core/io/http_client.cpp
index 52b1120b2ae4..45ae048a01e9 100644
--- a/core/io/http_client.cpp
+++ b/core/io/http_client.cpp
@@ -30,6 +30,10 @@
 
 #include "http_client.h"
 
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
+#include "core/variant/array.h"
+
 const char *HTTPClient::_methods[METHOD_MAX] = {
 	"GET",
 	"HEAD",
diff --git a/core/io/http_client.h b/core/io/http_client.h
index de6045f647c9..ac9373aef72a 100644
--- a/core/io/http_client.h
+++ b/core/io/http_client.h
@@ -31,10 +31,22 @@
 #ifndef HTTP_CLIENT_H
 #define HTTP_CLIENT_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/ip.h"
 #include "core/io/stream_peer.h"
 #include "core/io/stream_peer_tcp.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/variant.h"
+
+class StreamPeer;
 
 class HTTPClient : public RefCounted {
 	GDCLASS(HTTPClient, RefCounted);
diff --git a/core/io/http_client_tcp.cpp b/core/io/http_client_tcp.cpp
index f9207996774c..4030d9b91a62 100644
--- a/core/io/http_client_tcp.cpp
+++ b/core/io/http_client_tcp.cpp
@@ -32,7 +32,17 @@
 
 #include "http_client_tcp.h"
 
+#include <string.h>
+
+#include "core/error/error_macros.h"
+#include "core/io/http_client.h"
+#include "core/io/ip_address.h"
 #include "core/io/stream_peer_ssl.h"
+#include "core/object/object.h"
+#include "core/os/memory.h"
+#include "core/os/os.h"
+#include "core/string/char_utils.h"
+#include "core/typedefs.h"
 #include "core/version.h"
 
 HTTPClient *HTTPClientTCP::_create_func() {
diff --git a/core/io/http_client_tcp.h b/core/io/http_client_tcp.h
index c10e0b1ecae0..7a0c018b4587 100644
--- a/core/io/http_client_tcp.h
+++ b/core/io/http_client_tcp.h
@@ -31,6 +31,18 @@
 #ifndef HTTP_CLIENT_TCP_H
 #define HTTP_CLIENT_TCP_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/io/ip.h"
+#include "core/io/stream_peer.h"
+#include "core/io/stream_peer_tcp.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
+#include "core/variant/variant.h"
 #include "http_client.h"
 
 class HTTPClientTCP : public HTTPClient {
diff --git a/core/io/image.cpp b/core/io/image.cpp
index 577fc598075c..cda05b842b7f 100644
--- a/core/io/image.cpp
+++ b/core/io/image.cpp
@@ -30,17 +30,22 @@
 
 #include "image.h"
 
+#include <string.h>
+#include <cmath>
+
 #include "core/error/error_list.h"
 #include "core/error/error_macros.h"
 #include "core/io/image_loader.h"
 #include "core/io/resource_loader.h"
 #include "core/math/math_funcs.h"
-#include "core/string/print_string.h"
+#include "core/math/rect2i.h"
+#include "core/math/vector3.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/string/char_utils.h"
 #include "core/templates/hash_map.h"
 #include "core/variant/dictionary.h"
-
-#include <stdio.h>
-#include <cmath>
+#include "core/variant/variant.h"
 
 const char *Image::format_names[Image::FORMAT_MAX] = {
 	"Lum8", //luminance
diff --git a/core/io/image.h b/core/io/image.h
index 53bfa0881f77..9cad80d43222 100644
--- a/core/io/image.h
+++ b/core/io/image.h
@@ -31,9 +31,22 @@
 #ifndef IMAGE_H
 #define IMAGE_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
 #include "core/io/resource.h"
 #include "core/math/color.h"
 #include "core/math/rect2.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/dictionary.h"
 
 /**
  * Image storage class. This is used to store an image in user memory, as well as
diff --git a/core/io/image_loader.cpp b/core/io/image_loader.cpp
index 5518ec8ceb5f..cd2872ef8814 100644
--- a/core/io/image_loader.cpp
+++ b/core/io/image_loader.cpp
@@ -30,7 +30,13 @@
 
 #include "image_loader.h"
 
-#include "core/string/print_string.h"
+#include <stdint.h>
+
+#include "core/error/error_macros.h"
+#include "core/io/file_access.h"
+#include "core/io/image.h"
+#include "core/os/memory.h"
+#include "core/templates/vector.h"
 
 bool ImageFormatLoader::recognize(const String &p_extension) const {
 	List<String> extensions;
diff --git a/core/io/image_loader.h b/core/io/image_loader.h
index 37d7620f9675..057ef1851039 100644
--- a/core/io/image_loader.h
+++ b/core/io/image_loader.h
@@ -31,13 +31,20 @@
 #ifndef IMAGE_LOADER_H
 #define IMAGE_LOADER_H
 
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
 #include "core/io/image.h"
+#include "core/io/resource.h"
 #include "core/io/resource_loader.h"
+#include "core/object/ref_counted.h"
 #include "core/string/ustring.h"
 #include "core/templates/list.h"
 
 class ImageLoader;
+class FileAccess;
+class Image;
+template <class T>
+class Vector;
 
 class ImageFormatLoader {
 	friend class ImageLoader;
diff --git a/core/io/ip.cpp b/core/io/ip.cpp
index 8e0d47e7624e..cfcae81b4842 100644
--- a/core/io/ip.cpp
+++ b/core/io/ip.cpp
@@ -30,9 +30,17 @@
 
 #include "ip.h"
 
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/os/mutex.h"
 #include "core/os/semaphore.h"
 #include "core/os/thread.h"
 #include "core/templates/hash_map.h"
+#include "core/templates/pair.h"
+#include "core/templates/safe_refcount.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/variant.h"
 
 VARIANT_ENUM_CAST(IP::ResolverStatus);
 
diff --git a/core/io/ip.h b/core/io/ip.h
index 5602710550a8..7980486d8006 100644
--- a/core/io/ip.h
+++ b/core/io/ip.h
@@ -32,7 +32,13 @@
 #define IP_H
 
 #include "core/io/ip_address.h"
+#include "core/object/object.h"
 #include "core/os/os.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/variant/array.h"
+#include "core/variant/binder_common.h"
 
 struct _IP_ResolverPrivate;
 
diff --git a/core/io/ip_address.cpp b/core/io/ip_address.cpp
index d183c6079832..2c530e89849c 100644
--- a/core/io/ip_address.cpp
+++ b/core/io/ip_address.cpp
@@ -34,9 +34,12 @@ IPAddress::operator Variant() const {
 	return operator String();
 }*/
 
-#include <stdio.h>
 #include <string.h>
 
+#include "core/error/error_macros.h"
+#include "core/string/char_utils.h"
+#include "core/typedefs.h"
+
 IPAddress::operator String() const {
 	if (wildcard) {
 		return "*";
diff --git a/core/io/ip_address.h b/core/io/ip_address.h
index dc0c19bf48a7..6d14ddede208 100644
--- a/core/io/ip_address.h
+++ b/core/io/ip_address.h
@@ -31,6 +31,8 @@
 #ifndef IP_ADDRESS_H
 #define IP_ADDRESS_H
 
+#include <stdint.h>
+
 #include "core/string/ustring.h"
 
 struct IPAddress {
diff --git a/core/io/json.cpp b/core/io/json.cpp
index 4b745dff449a..afee90c208a5 100644
--- a/core/io/json.cpp
+++ b/core/io/json.cpp
@@ -30,7 +30,14 @@
 
 #include "json.h"
 
-#include "core/string/print_string.h"
+#include <math.h>
+
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
+#include "core/string/char_utils.h"
+#include "core/templates/list.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
 
 const char *JSON::tk_name[TK_MAX] = {
 	"'{'",
diff --git a/core/io/json.h b/core/io/json.h
index ed251938ecb6..6ab1fd377ea0 100644
--- a/core/io/json.h
+++ b/core/io/json.h
@@ -31,9 +31,16 @@
 #ifndef JSON_H
 #define JSON_H
 
+#include "core/error/error_list.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/set.h"
 #include "core/variant/variant.h"
 
+class Array;
+class Dictionary;
+
 class JSON : public RefCounted {
 	GDCLASS(JSON, RefCounted);
 
diff --git a/core/io/logger.cpp b/core/io/logger.cpp
index cb6369ae3d42..305c73fbe2f1 100644
--- a/core/io/logger.cpp
+++ b/core/io/logger.cpp
@@ -30,11 +30,16 @@
 
 #include "logger.h"
 
-#include "core/config/project_settings.h"
+#include <stdint.h>
+#include <stdio.h>
+
+#include "core/error/error_macros.h"
 #include "core/io/dir_access.h"
-#include "core/os/os.h"
+#include "core/io/file_access.h"
+#include "core/os/memory.h"
 #include "core/os/time.h"
 #include "core/string/print_string.h"
+#include "core/templates/set.h"
 
 #if defined(MINGW_ENABLED) || defined(_MSC_VER)
 #define sprintf sprintf_s
diff --git a/core/io/logger.h b/core/io/logger.h
index 047ee3d0f154..900e3d530844 100644
--- a/core/io/logger.h
+++ b/core/io/logger.h
@@ -31,11 +31,14 @@
 #ifndef LOGGER_H
 #define LOGGER_H
 
+#include <stdarg.h>
+
 #include "core/io/file_access.h"
 #include "core/string/ustring.h"
 #include "core/templates/vector.h"
+#include "core/typedefs.h"
 
-#include <stdarg.h>
+class FileAccess;
 
 class Logger {
 protected:
diff --git a/core/io/marshalls.cpp b/core/io/marshalls.cpp
index 555d4f6df428..a939019dadb6 100644
--- a/core/io/marshalls.cpp
+++ b/core/io/marshalls.cpp
@@ -30,12 +30,35 @@
 
 #include "marshalls.h"
 
-#include "core/object/ref_counted.h"
-#include "core/os/keyboard.h"
-#include "core/string/print_string.h"
-
 #include <limits.h>
 #include <stdio.h>
+#include <string.h>
+
+#include "core/error/error_macros.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
+#include "core/object/class_db.h"
+#include "core/object/ref_counted.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/rid.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
 
 void EncodedObjectAsID::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_object_id", "id"), &EncodedObjectAsID::set_object_id);
diff --git a/core/io/marshalls.h b/core/io/marshalls.h
index 4d7b98b74913..ab3dd96c668c 100644
--- a/core/io/marshalls.h
+++ b/core/io/marshalls.h
@@ -31,7 +31,13 @@
 #ifndef MARSHALLS_H
 #define MARSHALLS_H
 
+#include <stddef.h>
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/math/math_defs.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
 #include "core/object/ref_counted.h"
 #include "core/typedefs.h"
 #include "core/variant/variant.h"
diff --git a/core/io/net_socket.cpp b/core/io/net_socket.cpp
index 3e5246a1347a..5d39071f11c8 100644
--- a/core/io/net_socket.cpp
+++ b/core/io/net_socket.cpp
@@ -30,6 +30,8 @@
 
 #include "net_socket.h"
 
+#include "core/error/error_macros.h"
+
 NetSocket *(*NetSocket::_create)() = nullptr;
 
 NetSocket *NetSocket::create() {
diff --git a/core/io/net_socket.h b/core/io/net_socket.h
index 23eff17a6102..78c6a6831d25 100644
--- a/core/io/net_socket.h
+++ b/core/io/net_socket.h
@@ -31,8 +31,13 @@
 #ifndef NET_SOCKET_H
 #define NET_SOCKET_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/ip.h"
+#include "core/io/ip_address.h"
 #include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
 
 class NetSocket : public RefCounted {
 protected:
diff --git a/core/io/packed_data_container.cpp b/core/io/packed_data_container.cpp
index 14183b472b18..f61cc2c65cd8 100644
--- a/core/io/packed_data_container.cpp
+++ b/core/io/packed_data_container.cpp
@@ -30,8 +30,17 @@
 
 #include "packed_data_container.h"
 
-#include "core/core_string_names.h"
+#include <string.h>
+
+#include "core/error/error_macros.h"
 #include "core/io/marshalls.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
 
 Variant PackedDataContainer::getvar(const Variant &p_key, bool *r_valid) const {
 	bool err = false;
diff --git a/core/io/packed_data_container.h b/core/io/packed_data_container.h
index f042b364ee6b..89b7e7f3427c 100644
--- a/core/io/packed_data_container.h
+++ b/core/io/packed_data_container.h
@@ -31,7 +31,18 @@
 #ifndef PACKED_DATA_CONTAINER_H
 #define PACKED_DATA_CONTAINER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/resource.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/templates/map.h"
+#include "core/templates/vector.h"
+#include "core/variant/variant.h"
+
+class Array;
+class String;
 
 class PackedDataContainer : public Resource {
 	GDCLASS(PackedDataContainer, Resource);
diff --git a/core/io/packet_peer.cpp b/core/io/packet_peer.cpp
index 0af236f76665..07da9f39d3a6 100644
--- a/core/io/packet_peer.cpp
+++ b/core/io/packet_peer.cpp
@@ -31,7 +31,10 @@
 #include "packet_peer.h"
 
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/io/marshalls.h"
+#include "core/object/class_db.h"
+#include "core/typedefs.h"
 
 /* helpers / binders */
 
diff --git a/core/io/packet_peer.h b/core/io/packet_peer.h
index 0b126406279c..9ea00d08ac0f 100644
--- a/core/io/packet_peer.h
+++ b/core/io/packet_peer.h
@@ -31,13 +31,20 @@
 #ifndef PACKET_PEER_H
 #define PACKET_PEER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/stream_peer.h"
 #include "core/object/class_db.h"
-#include "core/templates/ring_buffer.h"
-
 #include "core/object/gdvirtual.gen.inc"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/string/string_name.h"
+#include "core/templates/ring_buffer.h"
+#include "core/templates/vector.h"
 #include "core/variant/native_ptr.h"
+#include "core/variant/variant.h"
 
 class PacketPeer : public RefCounted {
 	GDCLASS(PacketPeer, RefCounted);
diff --git a/core/io/packet_peer_dtls.cpp b/core/io/packet_peer_dtls.cpp
index 3c7ab28e12ab..95de0b9ea36a 100644
--- a/core/io/packet_peer_dtls.cpp
+++ b/core/io/packet_peer_dtls.cpp
@@ -29,8 +29,8 @@
 /*************************************************************************/
 
 #include "packet_peer_dtls.h"
-#include "core/config/project_settings.h"
-#include "core/io/file_access.h"
+
+#include "core/object/class_db.h"
 
 PacketPeerDTLS *(*PacketPeerDTLS::_create)() = nullptr;
 bool PacketPeerDTLS::available = false;
diff --git a/core/io/packet_peer_dtls.h b/core/io/packet_peer_dtls.h
index c5443d043e22..827bcd9e6530 100644
--- a/core/io/packet_peer_dtls.h
+++ b/core/io/packet_peer_dtls.h
@@ -32,7 +32,15 @@
 #define PACKET_PEER_DTLS_H
 
 #include "core/crypto/crypto.h"
+#include "core/error/error_list.h"
+#include "core/io/packet_peer.h"
 #include "core/io/packet_peer_udp.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/variant/binder_common.h"
+
+class PacketPeerUDP;
 
 class PacketPeerDTLS : public PacketPeer {
 	GDCLASS(PacketPeerDTLS, PacketPeer);
diff --git a/core/io/packet_peer_udp.cpp b/core/io/packet_peer_udp.cpp
index 503eb17cae25..fc112301849a 100644
--- a/core/io/packet_peer_udp.cpp
+++ b/core/io/packet_peer_udp.cpp
@@ -30,8 +30,12 @@
 
 #include "packet_peer_udp.h"
 
+#include "core/error/error_macros.h"
 #include "core/io/ip.h"
+#include "core/io/net_socket.h"
 #include "core/io/udp_server.h"
+#include "core/object/class_db.h"
+#include "core/typedefs.h"
 
 void PacketPeerUDP::set_blocking_mode(bool p_enable) {
 	blocking = p_enable;
diff --git a/core/io/packet_peer_udp.h b/core/io/packet_peer_udp.h
index 444a6dd5ba1b..48b441ffbbb1 100644
--- a/core/io/packet_peer_udp.h
+++ b/core/io/packet_peer_udp.h
@@ -31,11 +31,20 @@
 #ifndef PACKET_PEER_UDP_H
 #define PACKET_PEER_UDP_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/ip.h"
+#include "core/io/ip_address.h"
 #include "core/io/net_socket.h"
 #include "core/io/packet_peer.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/ring_buffer.h"
 
 class UDPServer;
+class NetSocket;
 
 class PacketPeerUDP : public PacketPeer {
 	GDCLASS(PacketPeerUDP, PacketPeer);
diff --git a/core/io/pck_packer.cpp b/core/io/pck_packer.cpp
index 272ace34383b..dc7b14f1b757 100644
--- a/core/io/pck_packer.cpp
+++ b/core/io/pck_packer.cpp
@@ -30,11 +30,19 @@
 
 #include "pck_packer.h"
 
+#include <stdio.h>
+
 #include "core/crypto/crypto_core.h"
+#include "core/error/error_macros.h"
 #include "core/io/file_access.h"
 #include "core/io/file_access_encrypted.h"
 #include "core/io/file_access_pack.h" // PACK_HEADER_MAGIC, PACK_FORMAT_VERSION
-#include "core/version.h"
+#include "core/math/math_funcs.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/string/char_utils.h"
+#include "core/typedefs.h"
+#include "core/version_generated.gen.h"
 
 static int _get_pad(int p_alignment, int p_n) {
 	int rest = p_n % p_alignment;
diff --git a/core/io/pck_packer.h b/core/io/pck_packer.h
index 583171a70bb9..696a287a5b80 100644
--- a/core/io/pck_packer.h
+++ b/core/io/pck_packer.h
@@ -31,7 +31,13 @@
 #ifndef PCK_PACKER_H
 #define PCK_PACKER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
 
 class FileAccess;
 
diff --git a/core/io/resource.cpp b/core/io/resource.cpp
index 66d5c54b53a6..806ef374e425 100644
--- a/core/io/resource.cpp
+++ b/core/io/resource.cpp
@@ -31,15 +31,20 @@
 #include "resource.h"
 
 #include "core/core_string_names.h"
+#include "core/error/error_macros.h"
 #include "core/io/file_access.h"
 #include "core/io/resource_loader.h"
 #include "core/math/math_funcs.h"
-#include "core/object/script_language.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/os/rw_lock.h"
+#include "core/string/print_string.h"
+#include "core/string/string_name.h"
+#include "core/templates/hashfuncs.h"
+#include "core/templates/pair.h"
+#include "core/variant/variant.h"
 #include "scene/main/node.h" //only so casting works
 
-#include <stdio.h>
-
 void Resource::emit_changed() {
 	emit_signal(CoreStringNames::get_singleton()->changed);
 }
diff --git a/core/io/resource.h b/core/io/resource.h
index b1e1c155412b..ab20d956c8d0 100644
--- a/core/io/resource.h
+++ b/core/io/resource.h
@@ -31,13 +31,26 @@
 #ifndef RESOURCE_H
 #define RESOURCE_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/resource_uid.h"
 #include "core/object/class_db.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
 #include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/hash_map.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/rid.h"
 #include "core/templates/safe_refcount.h"
 #include "core/templates/self_list.h"
+#include "core/templates/set.h"
+#include "core/typedefs.h"
 
 class Node;
+class RWLock;
 
 #define RES_BASE_EXTENSION(m_ext)                                                                                   \
 public:                                                                                                             \
diff --git a/core/io/resource_format_binary.cpp b/core/io/resource_format_binary.cpp
index 8588bab0be86..0f6717588fff 100644
--- a/core/io/resource_format_binary.cpp
+++ b/core/io/resource_format_binary.cpp
@@ -31,11 +31,34 @@
 #include "resource_format_binary.h"
 
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/io/dir_access.h"
+#include "core/io/file_access.h"
 #include "core/io/file_access_compressed.h"
-#include "core/io/image.h"
-#include "core/io/marshalls.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/math_defs.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/string/node_path.h"
+#include "core/templates/pair.h"
+#include "core/templates/rid.h"
+#include "core/variant/array.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
 #include "core/version.h"
+#include "core/version_generated.gen.h"
 
 //#define print_bl(m_what) print_line(m_what)
 #define print_bl(m_what) (void)(m_what)
diff --git a/core/io/resource_format_binary.h b/core/io/resource_format_binary.h
index ecc3e95f6b4b..5b94069bfe00 100644
--- a/core/io/resource_format_binary.h
+++ b/core/io/resource_format_binary.h
@@ -31,9 +31,26 @@
 #ifndef RESOURCE_FORMAT_BINARY_H
 #define RESOURCE_FORMAT_BINARY_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
+#include "core/io/resource.h"
 #include "core/io/resource_loader.h"
 #include "core/io/resource_saver.h"
+#include "core/io/resource_uid.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
+
+class FileAccess;
 
 class ResourceLoaderBinary {
 	bool translation_remapped = false;
diff --git a/core/io/resource_importer.cpp b/core/io/resource_importer.cpp
index 9b6440e2a2e5..e3b366fb23d2 100644
--- a/core/io/resource_importer.cpp
+++ b/core/io/resource_importer.cpp
@@ -31,7 +31,13 @@
 #include "resource_importer.h"
 
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
+#include "core/io/file_access.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/string/string_name.h"
+#include "core/templates/set.h"
 #include "core/variant/variant_parser.h"
 
 bool ResourceFormatImporter::SortImporterByName::operator()(const Ref<ResourceImporter> &p_a, const Ref<ResourceImporter> &p_b) const {
diff --git a/core/io/resource_importer.h b/core/io/resource_importer.h
index 2fffc16ad8dc..fac0096e1bfc 100644
--- a/core/io/resource_importer.h
+++ b/core/io/resource_importer.h
@@ -31,9 +31,23 @@
 #ifndef RESOURCE_IMPORTER_H
 #define RESOURCE_IMPORTER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/io/resource.h"
 #include "core/io/resource_loader.h"
+#include "core/io/resource_uid.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/vector.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/variant.h"
 
 class ResourceImporter;
+class StringName;
 
 class ResourceFormatImporter : public ResourceFormatLoader {
 	struct PathAndType {
diff --git a/core/io/resource_loader.cpp b/core/io/resource_loader.cpp
index 21bf566b1b3b..b024acbb8ef1 100644
--- a/core/io/resource_loader.cpp
+++ b/core/io/resource_loader.cpp
@@ -31,11 +31,19 @@
 #include "resource_loader.h"
 
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/io/file_access.h"
 #include "core/io/resource_importer.h"
+#include "core/object/class_db.h"
+#include "core/object/script_language.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/os/rw_lock.h"
+#include "core/os/semaphore.h"
 #include "core/string/print_string.h"
 #include "core/string/translation.h"
+#include "core/templates/pair.h"
+#include "core/variant/array.h"
 #include "core/variant/variant_parser.h"
 
 #ifdef DEBUG_LOAD_THREADED
diff --git a/core/io/resource_loader.h b/core/io/resource_loader.h
index a3fdefa0f12d..3c5b27ef4b1c 100644
--- a/core/io/resource_loader.h
+++ b/core/io/resource_loader.h
@@ -31,11 +31,31 @@
 #ifndef RESOURCE_LOADER_H
 #define RESOURCE_LOADER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/resource.h"
+#include "core/io/resource_uid.h"
 #include "core/object/gdvirtual.gen.inc"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/os/mutex.h"
 #include "core/os/semaphore.h"
 #include "core/os/thread.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/hash_map.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/self_list.h"
+#include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/variant.h"
+
+class Semaphore;
 
 class ResourceFormatLoader : public RefCounted {
 	GDCLASS(ResourceFormatLoader, RefCounted);
diff --git a/core/io/resource_saver.cpp b/core/io/resource_saver.cpp
index c883e8502f20..bbad02fd0b47 100644
--- a/core/io/resource_saver.cpp
+++ b/core/io/resource_saver.cpp
@@ -29,10 +29,14 @@
 /*************************************************************************/
 
 #include "resource_saver.h"
+
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/io/file_access.h"
 #include "core/io/resource_loader.h"
+#include "core/object/class_db.h"
 #include "core/object/script_language.h"
+#include "core/variant/variant.h"
 
 Ref<ResourceFormatSaver> ResourceSaver::saver[MAX_SAVERS];
 
diff --git a/core/io/resource_saver.h b/core/io/resource_saver.h
index 2919a4cec0a6..9971e40c4ca8 100644
--- a/core/io/resource_saver.h
+++ b/core/io/resource_saver.h
@@ -31,9 +31,19 @@
 #ifndef RESOURCE_SAVER_H
 #define RESOURCE_SAVER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/resource.h"
+#include "core/io/resource_uid.h"
 #include "core/object/gdvirtual.gen.inc"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
 
 class ResourceFormatSaver : public RefCounted {
 	GDCLASS(ResourceFormatSaver, RefCounted);
diff --git a/core/io/resource_uid.cpp b/core/io/resource_uid.cpp
index 776756e64e54..464525fba74c 100644
--- a/core/io/resource_uid.cpp
+++ b/core/io/resource_uid.cpp
@@ -30,10 +30,17 @@
 
 #include "resource_uid.h"
 
+#include <string.h>
+
 #include "core/config/project_settings.h"
 #include "core/crypto/crypto.h"
+#include "core/error/error_macros.h"
 #include "core/io/dir_access.h"
 #include "core/io/file_access.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/string/char_utils.h"
+#include "core/variant/variant.h"
 
 static constexpr uint32_t char_count = ('z' - 'a');
 static constexpr uint32_t base = char_count + ('9' - '0');
diff --git a/core/io/resource_uid.h b/core/io/resource_uid.h
index 9f2ab5245b47..f7a83d48c439 100644
--- a/core/io/resource_uid.h
+++ b/core/io/resource_uid.h
@@ -31,11 +31,18 @@
 #ifndef RESOURCE_UUID_H
 #define RESOURCE_UUID_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/os/mutex.h"
 #include "core/string/string_name.h"
+#include "core/string/ustring.h"
 #include "core/templates/ordered_hash_map.h"
 
 class Crypto;
+
 class ResourceUID : public Object {
 	GDCLASS(ResourceUID, Object)
 public:
diff --git a/core/io/stream_peer.cpp b/core/io/stream_peer.cpp
index c65968ef0338..002f9ff25f7c 100644
--- a/core/io/stream_peer.cpp
+++ b/core/io/stream_peer.cpp
@@ -30,7 +30,12 @@
 
 #include "stream_peer.h"
 
+#include <string.h>
+
+#include "core/error/error_macros.h"
 #include "core/io/marshalls.h"
+#include "core/object/class_db.h"
+#include "core/typedefs.h"
 
 Error StreamPeer::_put_data(const Vector<uint8_t> &p_data) {
 	int len = p_data.size();
diff --git a/core/io/stream_peer.h b/core/io/stream_peer.h
index e71941b7e181..f40a672ce538 100644
--- a/core/io/stream_peer.h
+++ b/core/io/stream_peer.h
@@ -31,11 +31,19 @@
 #ifndef STREAM_PEER_H
 #define STREAM_PEER_H
 
-#include "core/object/ref_counted.h"
+#include <stdint.h>
 
+#include "core/error/error_list.h"
 #include "core/object/gdvirtual.gen.inc"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
 #include "core/variant/native_ptr.h"
+#include "core/variant/variant.h"
 
 class StreamPeer : public RefCounted {
 	GDCLASS(StreamPeer, RefCounted);
diff --git a/core/io/stream_peer_ssl.cpp b/core/io/stream_peer_ssl.cpp
index ea8435e587d3..69e22880a327 100644
--- a/core/io/stream_peer_ssl.cpp
+++ b/core/io/stream_peer_ssl.cpp
@@ -30,7 +30,8 @@
 
 #include "stream_peer_ssl.h"
 
-#include "core/config/engine.h"
+#include "core/object/class_db.h"
+#include "core/variant/variant.h"
 
 StreamPeerSSL *(*StreamPeerSSL::_create)() = nullptr;
 
diff --git a/core/io/stream_peer_ssl.h b/core/io/stream_peer_ssl.h
index 15f646d89713..30a5cfecbddd 100644
--- a/core/io/stream_peer_ssl.h
+++ b/core/io/stream_peer_ssl.h
@@ -32,7 +32,12 @@
 #define STREAM_PEER_SSL_H
 
 #include "core/crypto/crypto.h"
+#include "core/error/error_list.h"
 #include "core/io/stream_peer.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/variant/binder_common.h"
 
 class StreamPeerSSL : public StreamPeer {
 	GDCLASS(StreamPeerSSL, StreamPeer);
diff --git a/core/io/stream_peer_tcp.cpp b/core/io/stream_peer_tcp.cpp
index 6d5784a8ab4a..91c18cdd1f49 100644
--- a/core/io/stream_peer_tcp.cpp
+++ b/core/io/stream_peer_tcp.cpp
@@ -31,6 +31,10 @@
 #include "stream_peer_tcp.h"
 
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
+#include "core/io/ip.h"
+#include "core/object/class_db.h"
+#include "core/os/os.h"
 
 Error StreamPeerTCP::_poll_connection() {
 	ERR_FAIL_COND_V(status != STATUS_CONNECTING || !_sock.is_valid() || !_sock->is_open(), FAILED);
diff --git a/core/io/stream_peer_tcp.h b/core/io/stream_peer_tcp.h
index f2c47b25cf4c..a0dfbceca636 100644
--- a/core/io/stream_peer_tcp.h
+++ b/core/io/stream_peer_tcp.h
@@ -31,10 +31,17 @@
 #ifndef STREAM_PEER_TCP_H
 #define STREAM_PEER_TCP_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/ip.h"
 #include "core/io/ip_address.h"
 #include "core/io/net_socket.h"
 #include "core/io/stream_peer.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/ustring.h"
+#include "core/variant/binder_common.h"
 
 class StreamPeerTCP : public StreamPeer {
 	GDCLASS(StreamPeerTCP, StreamPeer);
diff --git a/core/io/tcp_server.cpp b/core/io/tcp_server.cpp
index f1e745cf3656..50da558d6b0d 100644
--- a/core/io/tcp_server.cpp
+++ b/core/io/tcp_server.cpp
@@ -30,6 +30,13 @@
 
 #include "tcp_server.h"
 
+#include "core/error/error_macros.h"
+#include "core/io/ip.h"
+#include "core/io/net_socket.h"
+#include "core/io/stream_peer_tcp.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+
 void TCPServer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("listen", "port", "bind_address"), &TCPServer::listen, DEFVAL("*"));
 	ClassDB::bind_method(D_METHOD("is_connection_available"), &TCPServer::is_connection_available);
diff --git a/core/io/tcp_server.h b/core/io/tcp_server.h
index 2d427818a017..5bbe25ed49c1 100644
--- a/core/io/tcp_server.h
+++ b/core/io/tcp_server.h
@@ -31,10 +31,19 @@
 #ifndef TCP_SERVER_H
 #define TCP_SERVER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/ip.h"
+#include "core/io/ip_address.h"
 #include "core/io/net_socket.h"
 #include "core/io/stream_peer.h"
 #include "core/io/stream_peer_tcp.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+
+class NetSocket;
+class StreamPeerTCP;
 
 class TCPServer : public RefCounted {
 	GDCLASS(TCPServer, RefCounted);
diff --git a/core/io/translation_loader_po.cpp b/core/io/translation_loader_po.cpp
index 8d3e58cad1b7..478646ea0f92 100644
--- a/core/io/translation_loader_po.cpp
+++ b/core/io/translation_loader_po.cpp
@@ -30,9 +30,12 @@
 
 #include "translation_loader_po.h"
 
+#include "core/error/error_macros.h"
 #include "core/io/file_access.h"
-#include "core/string/translation.h"
+#include "core/object/ref_counted.h"
+#include "core/os/memory.h"
 #include "core/string/translation_po.h"
+#include "core/templates/vector.h"
 
 RES TranslationLoaderPO::load_translation(FileAccess *f, Error *r_error) {
 	enum Status {
diff --git a/core/io/translation_loader_po.h b/core/io/translation_loader_po.h
index 1c58896a00ca..8d5b4178c849 100644
--- a/core/io/translation_loader_po.h
+++ b/core/io/translation_loader_po.h
@@ -31,9 +31,15 @@
 #ifndef TRANSLATION_LOADER_PO_H
 #define TRANSLATION_LOADER_PO_H
 
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
+#include "core/io/resource.h"
 #include "core/io/resource_loader.h"
 #include "core/string/translation.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+
+class FileAccess;
 
 class TranslationLoaderPO : public ResourceFormatLoader {
 public:
diff --git a/core/io/udp_server.cpp b/core/io/udp_server.cpp
index 4934e3a7b69b..500225e16261 100644
--- a/core/io/udp_server.cpp
+++ b/core/io/udp_server.cpp
@@ -30,6 +30,14 @@
 
 #include "udp_server.h"
 
+#include "core/error/error_macros.h"
+#include "core/io/ip.h"
+#include "core/io/net_socket.h"
+#include "core/io/packet_peer_udp.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/variant/variant.h"
+
 void UDPServer::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("listen", "port", "bind_address"), &UDPServer::listen, DEFVAL("*"));
 	ClassDB::bind_method(D_METHOD("poll"), &UDPServer::poll);
diff --git a/core/io/udp_server.h b/core/io/udp_server.h
index 4a7546fddf2d..a54e6658199e 100644
--- a/core/io/udp_server.h
+++ b/core/io/udp_server.h
@@ -31,8 +31,18 @@
 #ifndef UDP_SERVER_H
 #define UDP_SERVER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/io/ip_address.h"
 #include "core/io/net_socket.h"
 #include "core/io/packet_peer_udp.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/templates/list.h"
+
+class NetSocket;
+class PacketPeerUDP;
 
 class UDPServer : public RefCounted {
 	GDCLASS(UDPServer, RefCounted);
diff --git a/core/io/xml_parser.cpp b/core/io/xml_parser.cpp
index 360da46f960a..d0921e5ee97e 100644
--- a/core/io/xml_parser.cpp
+++ b/core/io/xml_parser.cpp
@@ -30,7 +30,13 @@
 
 #include "xml_parser.h"
 
-#include "core/string/print_string.h"
+#include <string.h>
+
+#include "core/error/error_macros.h"
+#include "core/io/file_access.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/variant/binder_common.h"
 
 //#define DEBUG_XML
 
diff --git a/core/io/xml_parser.h b/core/io/xml_parser.h
index da14ee8eaee3..109cd973ef89 100644
--- a/core/io/xml_parser.h
+++ b/core/io/xml_parser.h
@@ -31,7 +31,11 @@
 #ifndef XML_PARSER_H
 #define XML_PARSER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
 #include "core/string/ustring.h"
 #include "core/templates/vector.h"
diff --git a/core/io/zip_io.cpp b/core/io/zip_io.cpp
index 2c4f8346ab45..8c5781abd13b 100644
--- a/core/io/zip_io.cpp
+++ b/core/io/zip_io.cpp
@@ -30,6 +30,14 @@
 
 #include "zip_io.h"
 
+#include <stdint.h>
+#include <string.h>
+
+#include "core/error/error_list.h"
+#include "core/io/file_access.h"
+#include "core/os/memory.h"
+#include "core/string/ustring.h"
+
 void *zipio_open(void *data, const char *p_fname, int mode) {
 	FileAccess *&f = *(FileAccess **)data;
 
diff --git a/core/io/zip_io.h b/core/io/zip_io.h
index 6a297034490b..d6daf6824c93 100644
--- a/core/io/zip_io.h
+++ b/core/io/zip_io.h
@@ -32,12 +32,15 @@
 #define ZIP_IO_H
 
 #include "core/io/file_access.h"
-
 // Not directly used in this header, but assumed available in downstream users
 // like platform/*/export/export.cpp. Could be fixed, but probably better to have
 // thirdparty includes in as little headers as possible.
+#include "thirdparty/minizip/ioapi.h"
 #include "thirdparty/minizip/unzip.h"
 #include "thirdparty/minizip/zip.h"
+#include "zconf.h"
+
+class FileAccess;
 
 void *zipio_open(void *data, const char *p_fname, int mode);
 uLong zipio_read(void *data, void *fdata, void *buf, uLong size);
diff --git a/core/math/a_star.cpp b/core/math/a_star.cpp
index 14057b96be9e..7aa2c4436a12 100644
--- a/core/math/a_star.cpp
+++ b/core/math/a_star.cpp
@@ -30,8 +30,14 @@
 
 #include "a_star.h"
 
+#include <initializer_list>
+
+#include "core/error/error_macros.h"
 #include "core/math/geometry_3d.h"
-#include "core/object/script_language.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
+#include "core/templates/sort_array.h"
+#include "core/variant/variant.h"
 
 int AStar::get_available_point_id() const {
 	if (points.has(last_free_id)) {
diff --git a/core/math/a_star.h b/core/math/a_star.h
index 130c202a6187..3131f7686594 100644
--- a/core/math/a_star.h
+++ b/core/math/a_star.h
@@ -31,10 +31,21 @@
 #ifndef A_STAR_H
 #define A_STAR_H
 
+#include <stdint.h>
+
+#include "core/math/math_defs.h"
+#include "core/math/vector2.h"
+#include "core/math/vector3.h"
 #include "core/object/gdvirtual.gen.inc"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/string/string_name.h"
 #include "core/templates/oa_hash_map.h"
+#include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
 
 /**
 	A* pathfinding algorithm.
diff --git a/core/math/aabb.cpp b/core/math/aabb.cpp
index 4c89be7f4d03..2f2e39b5c9ec 100644
--- a/core/math/aabb.cpp
+++ b/core/math/aabb.cpp
@@ -30,7 +30,6 @@
 
 #include "aabb.h"
 
-#include "core/string/print_string.h"
 #include "core/variant/variant.h"
 
 real_t AABB::get_volume() const {
diff --git a/core/math/aabb.h b/core/math/aabb.h
index cb6f05e9ea99..835e0a836d68 100644
--- a/core/math/aabb.h
+++ b/core/math/aabb.h
@@ -31,9 +31,13 @@
 #ifndef AABB_H
 #define AABB_H
 
+#include "core/error/error_macros.h"
 #include "core/math/math_defs.h"
+#include "core/math/math_funcs.h"
 #include "core/math/plane.h"
 #include "core/math/vector3.h"
+#include "core/string/ustring.h"
+#include "core/typedefs.h"
 
 /**
  * AABB (Axis Aligned Bounding Box)
diff --git a/core/math/basis.cpp b/core/math/basis.cpp
index a9b4651664db..55d559fcad7e 100644
--- a/core/math/basis.cpp
+++ b/core/math/basis.cpp
@@ -30,8 +30,10 @@
 
 #include "basis.h"
 
+#include <cmath>
+
+#include "core/error/error_macros.h"
 #include "core/math/math_funcs.h"
-#include "core/string/print_string.h"
 
 #define cofac(row1, col1, row2, col2) \
 	(elements[row1][col1] * elements[row2][col2] - elements[row1][col2] * elements[row2][col1])
diff --git a/core/math/basis.h b/core/math/basis.h
index 683f05150cc4..13a445c98baf 100644
--- a/core/math/basis.h
+++ b/core/math/basis.h
@@ -31,8 +31,11 @@
 #ifndef BASIS_H
 #define BASIS_H
 
+#include "core/math/math_defs.h"
 #include "core/math/quaternion.h"
 #include "core/math/vector3.h"
+#include "core/string/ustring.h"
+#include "core/typedefs.h"
 
 struct _NO_DISCARD_ Basis {
 	Vector3 elements[3] = {
diff --git a/core/math/camera_matrix.cpp b/core/math/camera_matrix.cpp
index f5d746ef0f7f..476cdae12c7e 100644
--- a/core/math/camera_matrix.cpp
+++ b/core/math/camera_matrix.cpp
@@ -30,12 +30,16 @@
 
 #include "camera_matrix.h"
 
+#include <math.h>
+
+#include "core/error/error_macros.h"
 #include "core/math/aabb.h"
+#include "core/math/basis.h"
 #include "core/math/math_funcs.h"
 #include "core/math/plane.h"
 #include "core/math/rect2.h"
 #include "core/math/transform_3d.h"
-#include "core/string/print_string.h"
+#include "core/math/vector2.h"
 
 float CameraMatrix::determinant() const {
 	return matrix[0][3] * matrix[1][2] * matrix[2][1] * matrix[3][0] - matrix[0][2] * matrix[1][3] * matrix[2][1] * matrix[3][0] -
diff --git a/core/math/camera_matrix.h b/core/math/camera_matrix.h
index 285d2ae384e4..8f3677066159 100644
--- a/core/math/camera_matrix.h
+++ b/core/math/camera_matrix.h
@@ -31,8 +31,14 @@
 #ifndef CAMERA_MATRIX_H
 #define CAMERA_MATRIX_H
 
+#include <stdint.h>
+
 #include "core/math/math_defs.h"
+#include "core/math/math_funcs.h"
 #include "core/math/vector3.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
 
 struct AABB;
 struct Plane;
diff --git a/core/math/color.cpp b/core/math/color.cpp
index b06d20b3d39c..d769e0771657 100644
--- a/core/math/color.cpp
+++ b/core/math/color.cpp
@@ -31,9 +31,8 @@
 #include "color.h"
 
 #include "color_names.inc"
+#include "core/error/error_macros.h"
 #include "core/math/math_funcs.h"
-#include "core/string/print_string.h"
-#include "core/templates/map.h"
 
 uint32_t Color::to_argb32() const {
 	uint32_t c = (uint8_t)Math::round(a * 255);
diff --git a/core/math/color.h b/core/math/color.h
index 72a4a5f8bee0..d3f7007f1c95 100644
--- a/core/math/color.h
+++ b/core/math/color.h
@@ -31,8 +31,13 @@
 #ifndef COLOR_H
 #define COLOR_H
 
+#include <stdint.h>
+#include <cmath>
+
+#include "core/math/math_defs.h"
 #include "core/math/math_funcs.h"
 #include "core/string/ustring.h"
+#include "core/typedefs.h"
 
 struct _NO_DISCARD_ Color {
 	union {
diff --git a/core/math/convex_hull.cpp b/core/math/convex_hull.cpp
index bd292f4c2adf..2413c04fa131 100644
--- a/core/math/convex_hull.cpp
+++ b/core/math/convex_hull.cpp
@@ -58,13 +58,14 @@ subject to the following restrictions:
 
 #include "convex_hull.h"
 
+#include <float.h>
+
 #include "core/error/error_macros.h"
 #include "core/math/aabb.h"
 #include "core/math/math_defs.h"
-#include "core/os/memory.h"
+#include "core/math/plane.h"
 #include "core/templates/paged_allocator.h"
-
-#include <string.h>
+#include "core/typedefs.h"
 
 //#define DEBUG_CONVEX_HULL
 //#define SHOW_ITERATIONS
diff --git a/core/math/convex_hull.h b/core/math/convex_hull.h
index bd86fe0eba73..2a9e40a97530 100644
--- a/core/math/convex_hull.h
+++ b/core/math/convex_hull.h
@@ -43,7 +43,11 @@ subject to the following restrictions:
 #ifndef CONVEX_HULL_H
 #define CONVEX_HULL_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/math/geometry_3d.h"
+#include "core/math/math_defs.h"
 #include "core/math/vector3.h"
 #include "core/templates/local_vector.h"
 #include "core/templates/vector.h"
diff --git a/core/math/dynamic_bvh.cpp b/core/math/dynamic_bvh.cpp
index 7aeb2aaaac76..bd3baaf43407 100644
--- a/core/math/dynamic_bvh.cpp
+++ b/core/math/dynamic_bvh.cpp
@@ -30,6 +30,8 @@
 
 #include "dynamic_bvh.h"
 
+#include <math.h>
+
 void DynamicBVH::_delete_node(Node *p_node) {
 	node_allocator.free(p_node);
 }
diff --git a/core/math/dynamic_bvh.h b/core/math/dynamic_bvh.h
index 50ec2c2b304e..f1a09bcfb429 100644
--- a/core/math/dynamic_bvh.h
+++ b/core/math/dynamic_bvh.h
@@ -31,7 +31,15 @@
 #ifndef DYNAMIC_BVH_H
 #define DYNAMIC_BVH_H
 
+#include <stdint.h>
+#include <string.h>
+
+#include "core/error/error_macros.h"
 #include "core/math/aabb.h"
+#include "core/math/math_defs.h"
+#include "core/math/math_funcs.h"
+#include "core/math/plane.h"
+#include "core/math/vector3.h"
 #include "core/templates/list.h"
 #include "core/templates/local_vector.h"
 #include "core/templates/paged_allocator.h"
diff --git a/core/math/expression.cpp b/core/math/expression.cpp
index 0ddac9744ef0..8042d48a46e9 100644
--- a/core/math/expression.cpp
+++ b/core/math/expression.cpp
@@ -30,12 +30,14 @@
 
 #include "expression.h"
 
-#include "core/io/marshalls.h"
-#include "core/math/math_funcs.h"
+#include <math.h>
+
+#include "core/error/error_macros.h"
+#include "core/math/math_defs.h"
 #include "core/object/class_db.h"
-#include "core/object/ref_counted.h"
-#include "core/os/os.h"
-#include "core/variant/variant_parser.h"
+#include "core/string/char_utils.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
 
 Error Expression::_get_token(Token &r_token) {
 	while (true) {
diff --git a/core/math/expression.h b/core/math/expression.h
index 9b87bdd6ec81..93b58ae0b1bd 100644
--- a/core/math/expression.h
+++ b/core/math/expression.h
@@ -31,7 +31,15 @@
 #ifndef EXPRESSION_H
 #define EXPRESSION_H
 
+#include "core/error/error_list.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/os/memory.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
+#include "core/variant/variant.h"
 
 class Expression : public RefCounted {
 	GDCLASS(Expression, RefCounted);
diff --git a/core/math/face3.cpp b/core/math/face3.cpp
index d588f34e5d00..298b419d9778 100644
--- a/core/math/face3.cpp
+++ b/core/math/face3.cpp
@@ -30,7 +30,11 @@
 
 #include "face3.h"
 
+#include "core/error/error_macros.h"
+#include "core/math/basis.h"
 #include "core/math/geometry_3d.h"
+#include "core/math/math_funcs.h"
+#include "core/math/transform_3d.h"
 
 int Face3::split_by_plane(const Plane &p_plane, Face3 p_res[3], bool p_is_point_over[3]) const {
 	ERR_FAIL_COND_V(is_degenerate(), 0);
diff --git a/core/math/face3.h b/core/math/face3.h
index 8b123f078cef..753b15e53faf 100644
--- a/core/math/face3.h
+++ b/core/math/face3.h
@@ -32,9 +32,14 @@
 #define FACE3_H
 
 #include "core/math/aabb.h"
+#include "core/math/math_defs.h"
 #include "core/math/plane.h"
 #include "core/math/transform_3d.h"
 #include "core/math/vector3.h"
+#include "core/string/ustring.h"
+#include "core/typedefs.h"
+
+struct Transform3D;
 
 struct _NO_DISCARD_ Face3 {
 	enum Side {
diff --git a/core/math/geometry_2d.cpp b/core/math/geometry_2d.cpp
index 9fa45a336307..00a4a021cc73 100644
--- a/core/math/geometry_2d.cpp
+++ b/core/math/geometry_2d.cpp
@@ -30,8 +30,15 @@
 
 #include "geometry_2d.h"
 
+#include <stdint.h>
+#include <string.h>
+#include <memory>
+
+#include "core/math/vector3i.h"
+#include "core/templates/list.h"
 #include "thirdparty/misc/clipper.hpp"
 #include "thirdparty/misc/polypartition.h"
+
 #define STB_RECT_PACK_IMPLEMENTATION
 #include "thirdparty/misc/stb_rect_pack.h"
 
diff --git a/core/math/geometry_2d.h b/core/math/geometry_2d.h
index a2881d5f607b..691290b96f38 100644
--- a/core/math/geometry_2d.h
+++ b/core/math/geometry_2d.h
@@ -31,7 +31,9 @@
 #ifndef GEOMETRY_2D_H
 #define GEOMETRY_2D_H
 
+#include "core/error/error_macros.h"
 #include "core/math/delaunay_2d.h"
+#include "core/math/math_defs.h"
 #include "core/math/math_funcs.h"
 #include "core/math/triangulate.h"
 #include "core/math/vector2.h"
@@ -39,6 +41,9 @@
 #include "core/math/vector3.h"
 #include "core/math/vector3i.h"
 #include "core/templates/vector.h"
+#include "core/typedefs.h"
+
+struct Vector3i;
 
 class Geometry2D {
 public:
diff --git a/core/math/geometry_3d.cpp b/core/math/geometry_3d.cpp
index a9ff46410e78..0f5a2301370d 100644
--- a/core/math/geometry_3d.cpp
+++ b/core/math/geometry_3d.cpp
@@ -30,10 +30,13 @@
 
 #include "geometry_3d.h"
 
-#include "core/string/print_string.h"
+#include <initializer_list>
 
-#include "thirdparty/misc/clipper.hpp"
-#include "thirdparty/misc/polypartition.h"
+#include "core/math/aabb.h"
+#include "core/math/face3.h"
+#include "core/math/vector3i.h"
+#include "core/os/memory.h"
+#include "core/templates/map.h"
 
 void Geometry3D::MeshData::optimize_vertices() {
 	Map<int, int> vtx_remap;
diff --git a/core/math/geometry_3d.h b/core/math/geometry_3d.h
index 0f6ab5c7161c..5eba2d2ec3b4 100644
--- a/core/math/geometry_3d.h
+++ b/core/math/geometry_3d.h
@@ -31,9 +31,22 @@
 #ifndef GEOMETRY_3D_H
 #define GEOMETRY_3D_H
 
+#include <stdint.h>
+
+#include "core/error/error_macros.h"
+#include "core/math/color.h"
 #include "core/math/face3.h"
+#include "core/math/math_defs.h"
+#include "core/math/math_funcs.h"
+#include "core/math/plane.h"
+#include "core/math/vector2.h"
+#include "core/math/vector3.h"
 #include "core/object/object.h"
 #include "core/templates/vector.h"
+#include "core/typedefs.h"
+
+struct Face3;
+struct Vector3i;
 
 class Geometry3D {
 public:
diff --git a/core/math/math_fieldwise.cpp b/core/math/math_fieldwise.cpp
index 1717ecd74bd4..f2bc2b8e3f6f 100644
--- a/core/math/math_fieldwise.cpp
+++ b/core/math/math_fieldwise.cpp
@@ -32,6 +32,17 @@
 
 #include "math_fieldwise.h"
 
+#include "core/error/error_macros.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector3.h"
+
 #define SETUP_TYPE(m_type)    \
 	m_type source = p_source; \
 	m_type target = p_target;
diff --git a/core/math/math_fieldwise.h b/core/math/math_fieldwise.h
index f8a5b7cbb264..3f04538fd0ab 100644
--- a/core/math/math_fieldwise.h
+++ b/core/math/math_fieldwise.h
@@ -31,6 +31,7 @@
 #ifndef MATH_FIELDWISE_H
 #define MATH_FIELDWISE_H
 
+#include "core/string/ustring.h"
 #ifdef TOOLS_ENABLED
 
 #include "core/variant/variant.h"
diff --git a/core/math/math_funcs.cpp b/core/math/math_funcs.cpp
index 614828d7cb71..bdaddde1ec84 100644
--- a/core/math/math_funcs.cpp
+++ b/core/math/math_funcs.cpp
@@ -31,6 +31,7 @@
 #include "math_funcs.h"
 
 #include "core/error/error_macros.h"
+#include "core/math/random_pcg.h"
 
 RandomPCG Math::default_rand(RandomPCG::DEFAULT_SEED, RandomPCG::DEFAULT_INC);
 
diff --git a/core/math/math_funcs.h b/core/math/math_funcs.h
index f3d10c3f0df8..95a149535eb1 100644
--- a/core/math/math_funcs.h
+++ b/core/math/math_funcs.h
@@ -31,14 +31,17 @@
 #ifndef MATH_FUNCS_H
 #define MATH_FUNCS_H
 
+#include <float.h>
+#include <math.h>
+#include <stdint.h>
+#include <cmath>
+
 #include "core/math/math_defs.h"
 #include "core/math/random_pcg.h"
 #include "core/typedefs.h"
-
 #include "thirdparty/misc/pcg.h"
 
-#include <float.h>
-#include <math.h>
+class RandomPCG;
 
 class Math {
 	static RandomPCG default_rand;
diff --git a/core/math/plane.h b/core/math/plane.h
index 66c17416624f..2754a15f633d 100644
--- a/core/math/plane.h
+++ b/core/math/plane.h
@@ -31,7 +31,10 @@
 #ifndef PLANE_H
 #define PLANE_H
 
+#include "core/math/math_defs.h"
 #include "core/math/vector3.h"
+#include "core/string/ustring.h"
+#include "core/typedefs.h"
 
 class Variant;
 
diff --git a/core/math/quaternion.cpp b/core/math/quaternion.cpp
index 2ce603cb139b..4b8372246a8e 100644
--- a/core/math/quaternion.cpp
+++ b/core/math/quaternion.cpp
@@ -31,7 +31,6 @@
 #include "quaternion.h"
 
 #include "core/math/basis.h"
-#include "core/string/print_string.h"
 
 real_t Quaternion::angle_to(const Quaternion &p_to) const {
 	real_t d = dot(p_to);
diff --git a/core/math/quaternion.h b/core/math/quaternion.h
index 7874e4f428c3..493f36508405 100644
--- a/core/math/quaternion.h
+++ b/core/math/quaternion.h
@@ -31,10 +31,12 @@
 #ifndef QUATERNION_H
 #define QUATERNION_H
 
+#include "core/error/error_macros.h"
 #include "core/math/math_defs.h"
 #include "core/math/math_funcs.h"
 #include "core/math/vector3.h"
 #include "core/string/ustring.h"
+#include "core/typedefs.h"
 
 struct _NO_DISCARD_ Quaternion {
 	union {
diff --git a/core/math/quick_hull.cpp b/core/math/quick_hull.cpp
index 8e87d44b7fe0..d635f2a197ed 100644
--- a/core/math/quick_hull.cpp
+++ b/core/math/quick_hull.cpp
@@ -30,7 +30,14 @@
 
 #include "quick_hull.h"
 
+#include "core/error/error_macros.h"
+#include "core/math/aabb.h"
+#include "core/math/math_defs.h"
+#include "core/math/math_funcs.h"
+#include "core/math/vector3.h"
 #include "core/templates/map.h"
+#include "core/templates/pair.h"
+#include "core/templates/set.h"
 
 uint32_t QuickHull::debug_stop_after = 0xFFFFFFFF;
 
diff --git a/core/math/quick_hull.h b/core/math/quick_hull.h
index b8d813c9795c..dbe1d9b44724 100644
--- a/core/math/quick_hull.h
+++ b/core/math/quick_hull.h
@@ -31,10 +31,18 @@
 #ifndef QUICK_HULL_H
 #define QUICK_HULL_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/math/aabb.h"
 #include "core/math/geometry_3d.h"
+#include "core/math/plane.h"
 #include "core/templates/list.h"
 #include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+
+struct Vector3;
 
 class QuickHull {
 public:
diff --git a/core/math/random_number_generator.cpp b/core/math/random_number_generator.cpp
index 31eeed439919..ee4eb9ca594d 100644
--- a/core/math/random_number_generator.cpp
+++ b/core/math/random_number_generator.cpp
@@ -30,6 +30,9 @@
 
 #include "random_number_generator.h"
 
+#include "core/object/class_db.h"
+#include "core/variant/variant.h"
+
 void RandomNumberGenerator::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("set_seed", "seed"), &RandomNumberGenerator::set_seed);
 	ClassDB::bind_method(D_METHOD("get_seed"), &RandomNumberGenerator::get_seed);
diff --git a/core/math/random_number_generator.h b/core/math/random_number_generator.h
index 9352bae0a675..751d98809931 100644
--- a/core/math/random_number_generator.h
+++ b/core/math/random_number_generator.h
@@ -31,8 +31,13 @@
 #ifndef RANDOM_NUMBER_GENERATOR_H
 #define RANDOM_NUMBER_GENERATOR_H
 
+#include <stdint.h>
+
+#include "core/math/math_defs.h"
 #include "core/math/random_pcg.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/typedefs.h"
 
 class RandomNumberGenerator : public RefCounted {
 	GDCLASS(RandomNumberGenerator, RefCounted);
diff --git a/core/math/random_pcg.cpp b/core/math/random_pcg.cpp
index c69986e6dfed..6dbc6e3ade48 100644
--- a/core/math/random_pcg.cpp
+++ b/core/math/random_pcg.cpp
@@ -30,6 +30,9 @@
 
 #include "random_pcg.h"
 
+#include <math.h>
+#include <stdlib.h>
+
 #include "core/os/os.h"
 
 RandomPCG::RandomPCG(uint64_t p_seed, uint64_t p_inc) :
diff --git a/core/math/random_pcg.h b/core/math/random_pcg.h
index 974dbbfc2e2f..d236950d2c11 100644
--- a/core/math/random_pcg.h
+++ b/core/math/random_pcg.h
@@ -31,16 +31,19 @@
 #ifndef RANDOM_PCG_H
 #define RANDOM_PCG_H
 
-#include "core/math/math_defs.h"
+#include <math.h>
+#include <stdint.h>
+#include <cmath>
 
+#include "core/math/math_defs.h"
+#include "core/typedefs.h"
 #include "thirdparty/misc/pcg.h"
 
-#include <math.h>
-
 #if defined(__GNUC__)
 #define CLZ32(x) __builtin_clz(x)
 #elif defined(_MSC_VER)
 #include <intrin.h>
+
 static int __bsr_clz32(uint32_t x) {
 	unsigned long index;
 	_BitScanReverse(&index, x);
@@ -55,6 +58,7 @@ static int __bsr_clz32(uint32_t x) {
 #define LDEXPF(s, e) __builtin_ldexpf(s, e)
 #else
 #include <math.h>
+
 #define LDEXP(s, e) ldexp(s, e)
 #define LDEXPF(s, e) ldexp(s, e)
 #endif
diff --git a/core/math/rect2.cpp b/core/math/rect2.cpp
index d6e20bdc3c94..18ba4d0e6e4b 100644
--- a/core/math/rect2.cpp
+++ b/core/math/rect2.cpp
@@ -32,6 +32,7 @@
 
 #include "core/math/rect2i.h"
 #include "core/math/transform_2d.h"
+#include "core/math/vector2i.h"
 #include "core/string/ustring.h"
 
 bool Rect2::is_equal_approx(const Rect2 &p_rect) const {
diff --git a/core/math/rect2.h b/core/math/rect2.h
index 6ecc02336c22..69499913477e 100644
--- a/core/math/rect2.h
+++ b/core/math/rect2.h
@@ -31,8 +31,12 @@
 #ifndef RECT2_H
 #define RECT2_H
 
+#include <stdint.h>
+
 #include "core/error/error_macros.h"
+#include "core/math/math_defs.h"
 #include "core/math/vector2.h"
+#include "core/typedefs.h"
 
 class String;
 struct Rect2i;
diff --git a/core/math/rect2i.cpp b/core/math/rect2i.cpp
index 0782c450d03e..515c04a225f4 100644
--- a/core/math/rect2i.cpp
+++ b/core/math/rect2i.cpp
@@ -31,6 +31,7 @@
 #include "rect2i.h"
 
 #include "core/math/rect2.h"
+#include "core/math/vector2.h"
 #include "core/string/ustring.h"
 
 Rect2i::operator String() const {
diff --git a/core/math/rect2i.h b/core/math/rect2i.h
index db1459a3e6bb..8e8cdcd7e489 100644
--- a/core/math/rect2i.h
+++ b/core/math/rect2i.h
@@ -31,8 +31,12 @@
 #ifndef RECT2I_H
 #define RECT2I_H
 
+#include <stdint.h>
+
 #include "core/error/error_macros.h"
+#include "core/math/math_defs.h"
 #include "core/math/vector2i.h"
+#include "core/typedefs.h"
 
 class String;
 struct Rect2;
diff --git a/core/math/static_raycaster.h b/core/math/static_raycaster.h
index 33254399c78a..e51e78475d15 100644
--- a/core/math/static_raycaster.h
+++ b/core/math/static_raycaster.h
@@ -31,7 +31,17 @@
 #ifndef STATIC_RAYCASTER_H
 #define STATIC_RAYCASTER_H
 
+#include <math.h>
+
+#include "core/math/vector3.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/templates/set.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
+
+template <class T>
+class Vector;
 
 #if !defined(__aligned)
 
diff --git a/core/math/transform_2d.h b/core/math/transform_2d.h
index f4546c13c8c1..e9f0696c509b 100644
--- a/core/math/transform_2d.h
+++ b/core/math/transform_2d.h
@@ -31,10 +31,13 @@
 #ifndef TRANSFORM_2D_H
 #define TRANSFORM_2D_H
 
+#include "core/error/error_macros.h"
+#include "core/math/math_defs.h"
 #include "core/math/math_funcs.h"
 #include "core/math/rect2.h"
 #include "core/math/vector2.h"
 #include "core/templates/vector.h"
+#include "core/typedefs.h"
 
 class String;
 
diff --git a/core/math/transform_3d.cpp b/core/math/transform_3d.cpp
index e5374315e2e2..6c633a9f2da7 100644
--- a/core/math/transform_3d.cpp
+++ b/core/math/transform_3d.cpp
@@ -30,8 +30,7 @@
 
 #include "transform_3d.h"
 
-#include "core/math/math_funcs.h"
-#include "core/string/print_string.h"
+#include "core/math/quaternion.h"
 
 void Transform3D::affine_invert() {
 	basis.invert();
diff --git a/core/math/transform_3d.h b/core/math/transform_3d.h
index 3b4762e2210a..90d9712601eb 100644
--- a/core/math/transform_3d.h
+++ b/core/math/transform_3d.h
@@ -33,7 +33,12 @@
 
 #include "core/math/aabb.h"
 #include "core/math/basis.h"
+#include "core/math/math_defs.h"
 #include "core/math/plane.h"
+#include "core/math/vector3.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
 
 struct _NO_DISCARD_ Transform3D {
 	Basis basis;
diff --git a/core/math/triangle_mesh.cpp b/core/math/triangle_mesh.cpp
index debc5cd00df7..4fc1c4a0844c 100644
--- a/core/math/triangle_mesh.cpp
+++ b/core/math/triangle_mesh.cpp
@@ -30,7 +30,18 @@
 
 #include "triangle_mesh.h"
 
+#include <stdint.h>
+
+#include "core/error/error_macros.h"
+#include "core/math/basis.h"
+#include "core/math/face3.h"
+#include "core/math/math_defs.h"
+#include "core/math/plane.h"
+#include "core/math/transform_3d.h"
+#include "core/templates/map.h"
+#include "core/templates/pair.h"
 #include "core/templates/sort_array.h"
+#include "core/typedefs.h"
 
 int TriangleMesh::_create_bvh(BVH *p_bvh, BVH **p_bb, int p_from, int p_size, int p_depth, int &r_max_depth, int &r_max_alloc) {
 	if (p_depth > r_max_depth) {
diff --git a/core/math/triangle_mesh.h b/core/math/triangle_mesh.h
index 1b99945698ee..080b24cc13df 100644
--- a/core/math/triangle_mesh.h
+++ b/core/math/triangle_mesh.h
@@ -31,8 +31,15 @@
 #ifndef TRIANGLE_MESH_H
 #define TRIANGLE_MESH_H
 
+#include "core/math/aabb.h"
 #include "core/math/face3.h"
+#include "core/math/vector3.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/templates/vector.h"
+
+struct Face3;
+struct Plane;
 
 class TriangleMesh : public RefCounted {
 	GDCLASS(TriangleMesh, RefCounted);
diff --git a/core/math/triangulate.cpp b/core/math/triangulate.cpp
index f3e3de5fc219..ad2f033a47a3 100644
--- a/core/math/triangulate.cpp
+++ b/core/math/triangulate.cpp
@@ -30,6 +30,8 @@
 
 #include "triangulate.h"
 
+#include "core/math/vector2.h"
+
 real_t Triangulate::get_area(const Vector<Vector2> &contour) {
 	int n = contour.size();
 	const Vector2 *c = &contour[0];
diff --git a/core/math/triangulate.h b/core/math/triangulate.h
index 0bfcfcb978dd..c66e93eeeac5 100644
--- a/core/math/triangulate.h
+++ b/core/math/triangulate.h
@@ -31,9 +31,12 @@
 #ifndef TRIANGULATE_H
 #define TRIANGULATE_H
 
+#include "core/math/math_defs.h"
 #include "core/math/vector2.h"
 #include "core/templates/vector.h"
 
+struct Vector2;
+
 /*
 https://www.flipcode.com/archives/Efficient_Polygon_Triangulation.shtml
 */
diff --git a/core/math/vector2.cpp b/core/math/vector2.cpp
index 40149e8cc19f..7378b37c99ea 100644
--- a/core/math/vector2.cpp
+++ b/core/math/vector2.cpp
@@ -30,6 +30,7 @@
 
 #include "vector2.h"
 
+#include "core/error/error_macros.h"
 #include "core/math/vector2i.h"
 #include "core/string/ustring.h"
 
diff --git a/core/math/vector2.h b/core/math/vector2.h
index 123e3dc7b64c..8caafc857001 100644
--- a/core/math/vector2.h
+++ b/core/math/vector2.h
@@ -31,7 +31,13 @@
 #ifndef VECTOR2_H
 #define VECTOR2_H
 
+#include <stdint.h>
+
+#include "core/math/math_defs.h"
 #include "core/math/math_funcs.h"
+#include "core/math/vector2i.h"
+#include "core/string/ustring.h"
+#include "core/typedefs.h"
 
 class String;
 struct Vector2i;
diff --git a/core/math/vector2i.cpp b/core/math/vector2i.cpp
index dfed42e4d6b0..41d4830c4a47 100644
--- a/core/math/vector2i.cpp
+++ b/core/math/vector2i.cpp
@@ -30,6 +30,7 @@
 
 #include "vector2i.h"
 
+#include "core/math/math_funcs.h"
 #include "core/math/vector2.h"
 #include "core/string/ustring.h"
 
diff --git a/core/math/vector2i.h b/core/math/vector2i.h
index 707c8c94900e..c32c15ba4215 100644
--- a/core/math/vector2i.h
+++ b/core/math/vector2i.h
@@ -31,7 +31,13 @@
 #ifndef VECTOR2I_H
 #define VECTOR2I_H
 
+#include <stdint.h>
+
+#include "core/math/math_defs.h"
 #include "core/math/math_funcs.h"
+#include "core/math/vector2.h"
+#include "core/string/ustring.h"
+#include "core/typedefs.h"
 
 class String;
 struct Vector2;
diff --git a/core/math/vector3.h b/core/math/vector3.h
index 345329f7f35e..a222e07549b5 100644
--- a/core/math/vector3.h
+++ b/core/math/vector3.h
@@ -31,10 +31,15 @@
 #ifndef VECTOR3_H
 #define VECTOR3_H
 
+#include <stdint.h>
+
+#include "core/error/error_macros.h"
+#include "core/math/math_defs.h"
 #include "core/math/math_funcs.h"
 #include "core/math/vector2.h"
 #include "core/math/vector3i.h"
 #include "core/string/ustring.h"
+#include "core/typedefs.h"
 
 struct Basis;
 
diff --git a/core/math/vector3i.cpp b/core/math/vector3i.cpp
index ac79b3c7ea4c..f3fa7af1f9e3 100644
--- a/core/math/vector3i.cpp
+++ b/core/math/vector3i.cpp
@@ -30,6 +30,8 @@
 
 #include "vector3i.h"
 
+#include "core/error/error_macros.h"
+
 void Vector3i::set_axis(const int p_axis, const int32_t p_value) {
 	ERR_FAIL_INDEX(p_axis, 3);
 	coord[p_axis] = p_value;
diff --git a/core/math/vector3i.h b/core/math/vector3i.h
index d166de80aa1f..a94d2e76359c 100644
--- a/core/math/vector3i.h
+++ b/core/math/vector3i.h
@@ -31,6 +31,8 @@
 #ifndef VECTOR3I_H
 #define VECTOR3I_H
 
+#include <stdint.h>
+
 #include "core/math/math_funcs.h"
 #include "core/string/ustring.h"
 #include "core/typedefs.h"
diff --git a/core/multiplayer/multiplayer_api.cpp b/core/multiplayer/multiplayer_api.cpp
index c8cb333e2c0a..3d0b7ffca273 100644
--- a/core/multiplayer/multiplayer_api.cpp
+++ b/core/multiplayer/multiplayer_api.cpp
@@ -30,10 +30,15 @@
 
 #include "multiplayer_api.h"
 
+#include <stdint.h>
+#include <string.h>
+
 #include "core/debugger/engine_debugger.h"
+#include "core/error/error_macros.h"
 #include "core/io/marshalls.h"
-
-#include <stdint.h>
+#include "core/object/callable_method_pointer.h"
+#include "core/object/class_db.h"
+#include "core/variant/array.h"
 
 #ifdef DEBUG_ENABLED
 #include "core/os/os.h"
diff --git a/core/multiplayer/multiplayer_api.h b/core/multiplayer/multiplayer_api.h
index 9fe67615e3b0..65dadfb79364 100644
--- a/core/multiplayer/multiplayer_api.h
+++ b/core/multiplayer/multiplayer_api.h
@@ -31,9 +31,19 @@
 #ifndef MULTIPLAYER_API_H
 #define MULTIPLAYER_API_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/multiplayer/multiplayer.h"
 #include "core/multiplayer/multiplayer_peer.h"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/variant/variant.h"
 
 class MultiplayerAPI;
 
diff --git a/core/multiplayer/multiplayer_peer.cpp b/core/multiplayer/multiplayer_peer.cpp
index ae3b139bccb5..d53e6d366deb 100644
--- a/core/multiplayer/multiplayer_peer.cpp
+++ b/core/multiplayer/multiplayer_peer.cpp
@@ -30,7 +30,12 @@
 
 #include "multiplayer_peer.h"
 
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
 #include "core/os/os.h"
+#include "core/string/ustring.h"
+#include "core/templates/hashfuncs.h"
+#include "core/variant/variant.h"
 
 uint32_t MultiplayerPeer::generate_unique_id() const {
 	uint32_t hash = 0;
diff --git a/core/multiplayer/multiplayer_peer.h b/core/multiplayer/multiplayer_peer.h
index dee2be7b4b0f..441951e4579c 100644
--- a/core/multiplayer/multiplayer_peer.h
+++ b/core/multiplayer/multiplayer_peer.h
@@ -31,11 +31,16 @@
 #ifndef NETWORKED_MULTIPLAYER_PEER_H
 #define NETWORKED_MULTIPLAYER_PEER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/io/packet_peer.h"
 #include "core/multiplayer/multiplayer.h"
-
 #include "core/object/gdvirtual.gen.inc"
+#include "core/object/object.h"
 #include "core/object/script_language.h"
+#include "core/string/string_name.h"
+#include "core/variant/binder_common.h"
 #include "core/variant/native_ptr.h"
 
 class MultiplayerPeer : public PacketPeer {
diff --git a/core/object/callable_method_pointer.cpp b/core/object/callable_method_pointer.cpp
index 1bf926cafca5..5758a7240cbc 100644
--- a/core/object/callable_method_pointer.cpp
+++ b/core/object/callable_method_pointer.cpp
@@ -30,6 +30,8 @@
 
 #include "callable_method_pointer.h"
 
+#include "core/templates/hashfuncs.h"
+
 bool CallableCustomMethodPointerBase::compare_equal(const CallableCustom *p_a, const CallableCustom *p_b) {
 	const CallableCustomMethodPointerBase *a = static_cast<const CallableCustomMethodPointerBase *>(p_a);
 	const CallableCustomMethodPointerBase *b = static_cast<const CallableCustomMethodPointerBase *>(p_b);
diff --git a/core/object/callable_method_pointer.h b/core/object/callable_method_pointer.h
index 53410a9acfc1..9c7b78d1e6b1 100644
--- a/core/object/callable_method_pointer.h
+++ b/core/object/callable_method_pointer.h
@@ -31,12 +31,22 @@
 #ifndef CALLABLE_METHOD_POINTER_H
 #define CALLABLE_METHOD_POINTER_H
 
+#include <stdint.h>
+#include <string.h>
+
+#include "core/error/error_macros.h"
 #include "core/object/object.h"
+#include "core/object/object_id.h"
+#include "core/os/memory.h"
+#include "core/string/ustring.h"
 #include "core/templates/hashfuncs.h"
 #include "core/templates/simple_type.h"
+#include "core/typedefs.h"
 #include "core/variant/binder_common.h"
 #include "core/variant/callable.h"
 
+class Variant;
+
 class CallableCustomMethodPointerBase : public CallableCustom {
 	uint32_t *comp_ptr;
 	uint32_t comp_size;
diff --git a/core/object/class_db.cpp b/core/object/class_db.cpp
index 72a98ca20c11..d24e1db4ebc1 100644
--- a/core/object/class_db.cpp
+++ b/core/object/class_db.cpp
@@ -31,7 +31,9 @@
 #include "class_db.h"
 
 #include "core/config/engine.h"
-#include "core/os/mutex.h"
+#include "core/os/rw_lock.h"
+#include "core/templates/hashfuncs.h"
+#include "core/variant/callable.h"
 #include "core/version.h"
 
 #define OBJTYPE_RLOCK RWLockRead _rw_lockr_(lock);
diff --git a/core/object/class_db.h b/core/object/class_db.h
index 5adf1a59a4ad..215239aaa0f2 100644
--- a/core/object/class_db.h
+++ b/core/object/class_db.h
@@ -31,9 +31,24 @@
 #ifndef CLASS_DB_H
 #define CLASS_DB_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
+#include "core/extension/gdnative_interface.h"
 #include "core/object/method_bind.h"
 #include "core/object/object.h"
+#include "core/os/memory.h"
 #include "core/string/print_string.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/hash_map.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
 
 /** To bind more then 6 parameters include this:
  *
@@ -443,4 +458,6 @@ _FORCE_INLINE_ Vector<Error> errarray(P... p_args) {
 
 #include "core/disabled_classes.gen.h"
 
+class RWLock;
+
 #endif // CLASS_DB_H
diff --git a/core/object/message_queue.cpp b/core/object/message_queue.cpp
index 3c828eabd97f..c9dc5fcd1288 100644
--- a/core/object/message_queue.cpp
+++ b/core/object/message_queue.cpp
@@ -32,7 +32,14 @@
 
 #include "core/config/project_settings.h"
 #include "core/core_string_names.h"
-#include "core/object/script_language.h"
+#include "core/error/error_macros.h"
+#include "core/object/object_id.h"
+#include "core/os/memory.h"
+#include "core/string/print_string.h"
+#include "core/string/ustring.h"
+#include "core/templates/map.h"
+#include "core/templates/pair.h"
+#include "core/typedefs.h"
 
 MessageQueue *MessageQueue::singleton = nullptr;
 
diff --git a/core/object/message_queue.h b/core/object/message_queue.h
index a4449cf47341..66f971c849bb 100644
--- a/core/object/message_queue.h
+++ b/core/object/message_queue.h
@@ -31,8 +31,17 @@
 #ifndef MESSAGE_QUEUE_H
 #define MESSAGE_QUEUE_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/object/class_db.h"
+#include "core/object/object.h"
 #include "core/os/thread_safe.h"
+#include "core/string/string_name.h"
+#include "core/variant/callable.h"
+#include "core/variant/variant.h"
+
+class ObjectID;
 
 class MessageQueue {
 	_THREAD_SAFE_CLASS_
diff --git a/core/object/method_bind.cpp b/core/object/method_bind.cpp
index 32269b5f1925..63cdecbd4ff9 100644
--- a/core/object/method_bind.cpp
+++ b/core/object/method_bind.cpp
@@ -30,9 +30,9 @@
 
 // object.h needs to be the first include *before* method_bind.h
 // FIXME: Find out why and fix potential cyclical dependencies.
-#include "core/object/object.h"
-
 #include "method_bind.h"
+#include "core/object/object.h"
+#include "core/templates/hashfuncs.h"
 
 uint32_t MethodBind::get_hash() const {
 	uint32_t hash = hash_djb2_one_32(has_return() ? 1 : 0);
diff --git a/core/object/method_bind.h b/core/object/method_bind.h
index 02b73fa273b4..fd87f2e672e3 100644
--- a/core/object/method_bind.h
+++ b/core/object/method_bind.h
@@ -31,7 +31,10 @@
 #ifndef METHOD_BIND_H
 #define METHOD_BIND_H
 
+#include <stdint.h>
+
 #include "core/variant/binder_common.h"
+#include "core/variant/typed_array.h"
 
 enum MethodFlags {
 	METHOD_FLAG_NORMAL = 1,
@@ -229,6 +232,7 @@ MethodBind *create_vararg_method_bind(Variant (T::*p_method)(const Variant **, i
 
 #ifndef TYPED_METHOD_BIND
 class __UnexistingClass;
+
 #define MB_T __UnexistingClass
 #else
 #define MB_T T
diff --git a/core/object/object.cpp b/core/object/object.cpp
index f966607e0324..52eab73927e7 100644
--- a/core/object/object.cpp
+++ b/core/object/object.cpp
@@ -30,11 +30,15 @@
 
 #include "object.h"
 
+#include "core/config/engine.h"
 #include "core/core_string_names.h"
 #include "core/io/resource.h"
 #include "core/object/class_db.h"
 #include "core/object/message_queue.h"
+#include "core/object/method_bind.h"
+#include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
 #include "core/string/print_string.h"
 #include "core/string/translation.h"
diff --git a/core/object/object.h b/core/object/object.h
index 1a0a81581d4e..8b0fb903c9b6 100644
--- a/core/object/object.h
+++ b/core/object/object.h
@@ -31,19 +31,35 @@
 #ifndef OBJECT_H
 #define OBJECT_H
 
+#include <stdint.h>
+#include <mutex>
+
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
 #include "core/extension/gdnative_interface.h"
 #include "core/object/object_id.h"
 #include "core/os/rw_lock.h"
 #include "core/os/spin_lock.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
 #include "core/templates/hash_map.h"
 #include "core/templates/list.h"
 #include "core/templates/map.h"
 #include "core/templates/safe_refcount.h"
 #include "core/templates/set.h"
+#include "core/templates/vector.h"
 #include "core/templates/vmap.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/callable.h"
 #include "core/variant/callable_bind.h"
+#include "core/variant/dictionary.h"
 #include "core/variant/variant.h"
 
+class ClassDB;
+class Object;
+
 #define VARIANT_ARG_LIST const Variant &p_arg1 = Variant(), const Variant &p_arg2 = Variant(), const Variant &p_arg3 = Variant(), const Variant &p_arg4 = Variant(), const Variant &p_arg5 = Variant(), const Variant &p_arg6 = Variant(), const Variant &p_arg7 = Variant(), const Variant &p_arg8 = Variant()
 #define VARIANT_ARG_PASS p_arg1, p_arg2, p_arg3, p_arg4, p_arg5, p_arg6, p_arg7, p_arg8
 #define VARIANT_ARG_DECLARE const Variant &p_arg1, const Variant &p_arg2, const Variant &p_arg3, const Variant &p_arg4, const Variant &p_arg5, const Variant &p_arg6, const Variant &p_arg7, const Variant &p_arg8
diff --git a/core/object/ref_counted.cpp b/core/object/ref_counted.cpp
index c9a7b2a608c8..dcc58088d838 100644
--- a/core/object/ref_counted.cpp
+++ b/core/object/ref_counted.cpp
@@ -30,6 +30,9 @@
 
 #include "ref_counted.h"
 
+#include <stdint.h>
+
+#include "core/object/class_db.h"
 #include "core/object/script_language.h"
 
 bool RefCounted::init_ref() {
diff --git a/core/object/ref_counted.h b/core/object/ref_counted.h
index 8eb1c97cceda..7fd925cc9010 100644
--- a/core/object/ref_counted.h
+++ b/core/object/ref_counted.h
@@ -31,8 +31,16 @@
 #ifndef REF_COUNTED_H
 #define REF_COUNTED_H
 
+#include "core/error/error_macros.h"
 #include "core/object/class_db.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
+#include "core/os/memory.h"
+#include "core/string/ustring.h"
 #include "core/templates/safe_refcount.h"
+#include "core/typedefs.h"
+#include "core/variant/type_info.h"
+#include "core/variant/variant.h"
 
 class RefCounted : public Object {
 	GDCLASS(RefCounted, Object);
diff --git a/core/object/script_language.cpp b/core/object/script_language.cpp
index 9fec7c397d52..0513d9487f02 100644
--- a/core/object/script_language.cpp
+++ b/core/object/script_language.cpp
@@ -31,11 +31,10 @@
 #include "script_language.h"
 
 #include "core/config/project_settings.h"
-#include "core/core_string_names.h"
 #include "core/debugger/engine_debugger.h"
 #include "core/debugger/script_debugger.h"
-
-#include <stdint.h>
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
 
 ScriptLanguage *ScriptServer::_languages[MAX_LANGUAGES];
 int ScriptServer::_language_count = 0;
diff --git a/core/object/script_language.h b/core/object/script_language.h
index 4b18d9a5e856..3ed27aa4d695 100644
--- a/core/object/script_language.h
+++ b/core/object/script_language.h
@@ -31,11 +31,28 @@
 #ifndef SCRIPT_LANGUAGE_H
 #define SCRIPT_LANGUAGE_H
 
+#include <stdint.h>
+
 #include "core/doc_data.h"
+#include "core/error/error_list.h"
 #include "core/io/resource.h"
+#include "core/math/color.h"
 #include "core/multiplayer/multiplayer.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/hash_map.h"
+#include "core/templates/list.h"
 #include "core/templates/map.h"
 #include "core/templates/pair.h"
+#include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/variant.h"
 
 class ScriptLanguage;
 
diff --git a/core/object/undo_redo.cpp b/core/object/undo_redo.cpp
index f72dec8edf83..a28d1c2eb035 100644
--- a/core/object/undo_redo.cpp
+++ b/core/object/undo_redo.cpp
@@ -30,9 +30,14 @@
 
 #include "undo_redo.h"
 
+#include "core/error/error_macros.h"
 #include "core/io/resource.h"
+#include "core/object/class_db.h"
+#include "core/object/method_bind.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
 #include "core/templates/local_vector.h"
+#include "core/typedefs.h"
 
 void UndoRedo::_discard_redo() {
 	if (current_action == actions.size() - 1) {
diff --git a/core/object/undo_redo.h b/core/object/undo_redo.h
index 75639f8abfe6..525c3b868495 100644
--- a/core/object/undo_redo.h
+++ b/core/object/undo_redo.h
@@ -31,8 +31,19 @@
 #ifndef UNDO_REDO_H
 #define UNDO_REDO_H
 
+#include <stdint.h>
+
 #include "core/object/class_db.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
 #include "core/object/ref_counted.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/callable.h"
+#include "core/variant/variant.h"
 
 class UndoRedo : public Object {
 	GDCLASS(UndoRedo, Object);
diff --git a/core/os/keyboard.cpp b/core/os/keyboard.cpp
index 3a03c0a10bc0..77acf6dd42e8 100644
--- a/core/os/keyboard.cpp
+++ b/core/os/keyboard.cpp
@@ -30,8 +30,6 @@
 
 #include "keyboard.h"
 
-#include "core/os/os.h"
-
 struct _KeyCodeText {
 	Key code;
 	const char *text;
diff --git a/core/os/keyboard.h b/core/os/keyboard.h
index a21d81b2e7d8..000e21dc89a9 100644
--- a/core/os/keyboard.h
+++ b/core/os/keyboard.h
@@ -31,6 +31,8 @@
 #ifndef KEYBOARD_H
 #define KEYBOARD_H
 
+#include <stdint.h>
+
 #include "core/string/ustring.h"
 
 enum class Key {
diff --git a/core/os/main_loop.cpp b/core/os/main_loop.cpp
index a96e1989f9f7..97a35075e012 100644
--- a/core/os/main_loop.cpp
+++ b/core/os/main_loop.cpp
@@ -30,7 +30,9 @@
 
 #include "main_loop.h"
 
+#include "core/object/class_db.h"
 #include "core/object/script_language.h"
+#include "core/variant/variant.h"
 
 void MainLoop::_bind_methods() {
 	BIND_CONSTANT(NOTIFICATION_OS_MEMORY_WARNING);
diff --git a/core/os/main_loop.h b/core/os/main_loop.h
index a6a32f013878..19aa320793af 100644
--- a/core/os/main_loop.h
+++ b/core/os/main_loop.h
@@ -33,8 +33,11 @@
 
 #include "core/input/input_event.h"
 #include "core/object/gdvirtual.gen.inc"
+#include "core/object/object.h"
 #include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
 
 class MainLoop : public Object {
 	GDCLASS(MainLoop, Object);
diff --git a/core/os/memory.cpp b/core/os/memory.cpp
index 6ff0f9ae005b..3057f17068ff 100644
--- a/core/os/memory.cpp
+++ b/core/os/memory.cpp
@@ -30,12 +30,12 @@
 
 #include "memory.h"
 
+#include <stdlib.h>
+#include <cstdint>
+
 #include "core/error/error_macros.h"
 #include "core/templates/safe_refcount.h"
 
-#include <stdio.h>
-#include <stdlib.h>
-
 void *operator new(size_t p_size, const char *p_description) {
 	return Memory::alloc_static(p_size, false);
 }
diff --git a/core/os/memory.h b/core/os/memory.h
index 27eaad5010a4..2058d83b89cc 100644
--- a/core/os/memory.h
+++ b/core/os/memory.h
@@ -31,11 +31,16 @@
 #ifndef MEMORY_H
 #define MEMORY_H
 
+#include <stddef.h>
+#include <stdint.h>
+#include <new>
+
 #include "core/error/error_macros.h"
 #include "core/templates/safe_refcount.h"
+#include "core/typedefs.h"
 
-#include <stddef.h>
-#include <new>
+template <class T>
+class SafeNumeric;
 
 #ifndef PAD_ALIGN
 #define PAD_ALIGN 16 //must always be greater than this at much
diff --git a/core/os/midi_driver.cpp b/core/os/midi_driver.cpp
index 8431ceacf946..e9be7d58f5a6 100644
--- a/core/os/midi_driver.cpp
+++ b/core/os/midi_driver.cpp
@@ -31,7 +31,9 @@
 #include "midi_driver.h"
 
 #include "core/input/input.h"
-#include "core/os/os.h"
+#include "core/input/input_enums.h"
+#include "core/input/input_event.h"
+#include "core/object/ref_counted.h"
 
 uint8_t MIDIDriver::last_received_message = 0x00;
 MIDIDriver *MIDIDriver::singleton = nullptr;
diff --git a/core/os/midi_driver.h b/core/os/midi_driver.h
index c23614af00e9..0424feaa0724 100644
--- a/core/os/midi_driver.h
+++ b/core/os/midi_driver.h
@@ -31,6 +31,9 @@
 #ifndef MIDI_DRIVER_H
 #define MIDI_DRIVER_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/typedefs.h"
 #include "core/variant/variant.h"
 
diff --git a/core/os/os.cpp b/core/os/os.cpp
index 0032e8e4bc95..42b0b4677109 100644
--- a/core/os/os.cpp
+++ b/core/os/os.cpp
@@ -30,15 +30,21 @@
 
 #include "os.h"
 
+#include <stdarg.h>
+#include <stdio.h>
+
+#include "core/config/engine.h"
 #include "core/config/project_settings.h"
-#include "core/input/input.h"
+#include "core/error/error_macros.h"
 #include "core/io/dir_access.h"
 #include "core/io/file_access.h"
+#include "core/io/resource.h"
+#include "core/object/object.h"
+#include "core/os/memory.h"
 #include "core/os/midi_driver.h"
+#include "core/string/print_string.h"
 #include "core/version_generated.gen.h"
 
-#include <stdarg.h>
-
 OS *OS::singleton = nullptr;
 uint64_t OS::target_ticks = 0;
 
diff --git a/core/os/os.h b/core/os/os.h
index 36d85da70be1..fae567e2d48a 100644
--- a/core/os/os.h
+++ b/core/os/os.h
@@ -31,16 +31,24 @@
 #ifndef OS_H
 #define OS_H
 
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdlib.h>
+
 #include "core/config/engine.h"
+#include "core/error/error_list.h"
 #include "core/io/image.h"
 #include "core/io/logger.h"
+#include "core/math/vector2.h"
 #include "core/os/main_loop.h"
+#include "core/os/mutex.h"
 #include "core/string/ustring.h"
 #include "core/templates/list.h"
 #include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
 
-#include <stdarg.h>
-#include <stdlib.h>
+class MainLoop;
 
 class OS {
 	static OS *singleton;
diff --git a/core/os/pool_allocator.cpp b/core/os/pool_allocator.cpp
index 190617f9678f..c4237ba9cef8 100644
--- a/core/os/pool_allocator.cpp
+++ b/core/os/pool_allocator.cpp
@@ -30,12 +30,11 @@
 
 #include "pool_allocator.h"
 
+#include <string.h>
+
 #include "core/error/error_macros.h"
 #include "core/os/memory.h"
 #include "core/os/os.h"
-#include "core/string/print_string.h"
-
-#include <assert.h>
 
 #define COMPACT_CHUNK(m_entry, m_to_pos)                      \
 	do {                                                      \
diff --git a/core/os/pool_allocator.h b/core/os/pool_allocator.h
index 11a252bc541c..67a2878eba98 100644
--- a/core/os/pool_allocator.h
+++ b/core/os/pool_allocator.h
@@ -31,6 +31,9 @@
 #ifndef POOL_ALLOCATOR_H
 #define POOL_ALLOCATOR_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/typedefs.h"
 
 /**
diff --git a/core/os/thread.cpp b/core/os/thread.cpp
index f80e8f4bb34f..4ed0cc0716b3 100644
--- a/core/os/thread.cpp
+++ b/core/os/thread.cpp
@@ -32,12 +32,12 @@
 
 #include "thread.h"
 
+#include "core/error/error_macros.h"
 #include "core/object/script_language.h"
+#include "core/string/ustring.h"
 
 #if !defined(NO_THREADS)
 
-#include "core/templates/safe_refcount.h"
-
 Error (*Thread::set_name_func)(const String &) = nullptr;
 void (*Thread::set_priority_func)(Thread::Priority) = nullptr;
 void (*Thread::init_func)() = nullptr;
diff --git a/core/os/thread.h b/core/os/thread.h
index f4e46059ad47..cba3bcc7b61f 100644
--- a/core/os/thread.h
+++ b/core/os/thread.h
@@ -32,6 +32,9 @@
 // to use a custom Thread implementation defined in `platform/[your_platform]/platform_thread.h`
 // Overriding the platform implementation is required in some proprietary platforms
 #ifdef PLATFORM_THREAD_OVERRIDE
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "platform_thread.h"
 #else
 #ifndef THREAD_H
@@ -40,8 +43,9 @@
 #include "core/typedefs.h"
 
 #if !defined(NO_THREADS)
-#include "core/templates/safe_refcount.h"
 #include <thread>
+
+#include "core/templates/safe_refcount.h"
 #endif
 
 class String;
diff --git a/core/os/time.cpp b/core/os/time.cpp
index 5eae94279a5d..ee7be607c40c 100644
--- a/core/os/time.cpp
+++ b/core/os/time.cpp
@@ -30,7 +30,14 @@
 
 #include "time.h"
 
+#include "core/error/error_macros.h"
+#include "core/math/math_funcs.h"
+#include "core/object/class_db.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/templates/vector.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/variant.h"
 
 #define UNIX_EPOCH_YEAR_AD 1970 // 1970
 #define SECONDS_PER_DAY (24 * 60 * 60) // 86400
diff --git a/core/os/time.h b/core/os/time.h
index 3f00ba147822..3f241186a3c6 100644
--- a/core/os/time.h
+++ b/core/os/time.h
@@ -31,7 +31,12 @@
 #ifndef TIME_H
 #define TIME_H
 
+#include <stdint.h>
+
 #include "core/object/class_db.h"
+#include "core/object/object.h"
+#include "core/string/ustring.h"
+#include "core/variant/dictionary.h"
 
 // This Time class conforms with as many of the ISO 8601 standards as possible.
 // * As per ISO 8601:2004 4.3.2.1, all dates follow the Proleptic Gregorian
diff --git a/core/register_core_types.cpp b/core/register_core_types.cpp
index 388368d1812d..dc2154b51f02 100644
--- a/core/register_core_types.cpp
+++ b/core/register_core_types.cpp
@@ -36,7 +36,6 @@
 #include "core/core_string_names.h"
 #include "core/crypto/aes_context.h"
 #include "core/crypto/crypto.h"
-#include "core/crypto/hashing_context.h"
 #include "core/extension/native_extension.h"
 #include "core/extension/native_extension_manager.h"
 #include "core/input/input.h"
@@ -46,35 +45,89 @@
 #include "core/io/dtls_server.h"
 #include "core/io/http_client.h"
 #include "core/io/image_loader.h"
+#include "core/io/ip.h"
 #include "core/io/json.h"
 #include "core/io/marshalls.h"
 #include "core/io/packed_data_container.h"
-#include "core/io/packet_peer.h"
 #include "core/io/packet_peer_dtls.h"
-#include "core/io/packet_peer_udp.h"
 #include "core/io/pck_packer.h"
+#include "core/io/resource.h"
 #include "core/io/resource_format_binary.h"
 #include "core/io/resource_importer.h"
+#include "core/io/resource_loader.h"
+#include "core/io/resource_saver.h"
 #include "core/io/resource_uid.h"
 #include "core/io/stream_peer_ssl.h"
 #include "core/io/tcp_server.h"
 #include "core/io/translation_loader_po.h"
 #include "core/io/udp_server.h"
-#include "core/io/xml_parser.h"
 #include "core/math/a_star.h"
 #include "core/math/expression.h"
-#include "core/math/geometry_2d.h"
-#include "core/math/geometry_3d.h"
 #include "core/math/random_number_generator.h"
 #include "core/math/triangle_mesh.h"
 #include "core/multiplayer/multiplayer_api.h"
 #include "core/multiplayer/multiplayer_peer.h"
 #include "core/object/class_db.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
 #include "core/object/undo_redo.h"
-#include "core/os/main_loop.h"
+#include "core/os/memory.h"
+#include "core/os/mutex.h"
 #include "core/os/time.h"
 #include "core/string/optimized_translation.h"
-#include "core/string/translation.h"
+#include "core/string/string_name.h"
+#include "core/variant/callable.h"
+#include "core/variant/variant.h"
+
+class AESContext;
+class AStar2D;
+class AStar;
+class ConfigFile;
+class EncodedObjectAsID;
+class Expression;
+class HashingContext;
+class Image;
+class InputEvent;
+class InputEventAction;
+class InputEventFromWindow;
+class InputEventGesture;
+class InputEventJoypadButton;
+class InputEventJoypadMotion;
+class InputEventKey;
+class InputEventMIDI;
+class InputEventMagnifyGesture;
+class InputEventMouse;
+class InputEventMouseButton;
+class InputEventMouseMotion;
+class InputEventPanGesture;
+class InputEventScreenDrag;
+class InputEventScreenTouch;
+class InputEventShortcut;
+class InputEventWithModifiers;
+class JSON;
+class MainLoop;
+class MultiplayerAPI;
+class MultiplayerPeer;
+class MultiplayerPeerExtension;
+class OptimizedTranslation;
+class PCKPacker;
+class PackedDataContainer;
+class PackedDataContainerRef;
+class PacketPeer;
+class PacketPeerExtension;
+class PacketPeerStream;
+class PacketPeerUDP;
+class RandomNumberGenerator;
+class Script;
+class StreamPeer;
+class StreamPeerBuffer;
+class StreamPeerExtension;
+class StreamPeerTCP;
+class TCPServer;
+class TriangleMesh;
+class UDPServer;
+class UndoRedo;
+class XMLParser;
 
 static Ref<ResourceFormatSaverBinary> resource_saver_binary;
 static Ref<ResourceFormatLoaderBinary> resource_loader_binary;
diff --git a/core/string/node_path.cpp b/core/string/node_path.cpp
index 238897c2b179..9589663daead 100644
--- a/core/string/node_path.cpp
+++ b/core/string/node_path.cpp
@@ -30,7 +30,8 @@
 
 #include "node_path.h"
 
-#include "core/string/print_string.h"
+#include "core/error/error_macros.h"
+#include "core/os/memory.h"
 
 void NodePath::_update_hash_cache() const {
 	uint32_t h = data->absolute ? 1 : 0;
diff --git a/core/string/node_path.h b/core/string/node_path.h
index 53976bd52472..9a8c99e911b3 100644
--- a/core/string/node_path.h
+++ b/core/string/node_path.h
@@ -31,8 +31,13 @@
 #ifndef NODE_PATH_H
 #define NODE_PATH_H
 
+#include <stdint.h>
+
 #include "core/string/string_name.h"
 #include "core/string/ustring.h"
+#include "core/templates/safe_refcount.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
 
 class NodePath {
 	struct Data {
diff --git a/core/string/optimized_translation.cpp b/core/string/optimized_translation.cpp
index 07b58f241877..6f245731aca2 100644
--- a/core/string/optimized_translation.cpp
+++ b/core/string/optimized_translation.cpp
@@ -30,6 +30,13 @@
 
 #include "optimized_translation.h"
 
+#include <string.h>
+
+#include "core/error/error_macros.h"
+#include "core/math/math_funcs.h"
+#include "core/object/class_db.h"
+#include "core/string/ustring.h"
+#include "core/templates/map.h"
 #include "core/templates/pair.h"
 
 extern "C" {
diff --git a/core/string/optimized_translation.h b/core/string/optimized_translation.h
index f3dbfe8f5c4f..e376b14a9c51 100644
--- a/core/string/optimized_translation.h
+++ b/core/string/optimized_translation.h
@@ -31,7 +31,16 @@
 #ifndef OPTIMIZED_TRANSLATION_H
 #define OPTIMIZED_TRANSLATION_H
 
+#include <stdint.h>
+
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/string_name.h"
 #include "core/string/translation.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/variant.h"
 
 class OptimizedTranslation : public Translation {
 	GDCLASS(OptimizedTranslation, Translation);
diff --git a/core/string/print_string.cpp b/core/string/print_string.cpp
index 97e119bcf626..f3c2592e2d89 100644
--- a/core/string/print_string.cpp
+++ b/core/string/print_string.cpp
@@ -30,9 +30,9 @@
 
 #include "print_string.h"
 
+#include "core/error/error_macros.h"
 #include "core/os/os.h"
-
-#include <stdio.h>
+#include "core/typedefs.h"
 
 static PrintHandlerList *print_handler_list = nullptr;
 bool _print_line_enabled = true;
diff --git a/core/string/print_string.h b/core/string/print_string.h
index 669d2ea31657..cf0e5279a8ac 100644
--- a/core/string/print_string.h
+++ b/core/string/print_string.h
@@ -31,6 +31,7 @@
 #ifndef PRINT_STRING_H
 #define PRINT_STRING_H
 
+#include "core/string/ustring.h"
 #include "core/variant/variant.h"
 
 extern void (*_print_func)(String);
diff --git a/core/string/string_builder.cpp b/core/string/string_builder.cpp
index 7359ff59e11b..f9853d2046d5 100644
--- a/core/string/string_builder.cpp
+++ b/core/string/string_builder.cpp
@@ -32,6 +32,8 @@
 
 #include <string.h>
 
+#include "core/os/memory.h"
+
 StringBuilder &StringBuilder::append(const String &p_string) {
 	if (p_string.is_empty()) {
 		return *this;
diff --git a/core/string/string_builder.h b/core/string/string_builder.h
index 897efa95ef08..9059777e10c2 100644
--- a/core/string/string_builder.h
+++ b/core/string/string_builder.h
@@ -31,8 +31,11 @@
 #ifndef STRING_BUILDER_H
 #define STRING_BUILDER_H
 
+#include <stdint.h>
+
 #include "core/string/ustring.h"
 #include "core/templates/vector.h"
+#include "core/typedefs.h"
 
 class StringBuilder {
 	uint32_t string_length = 0;
diff --git a/core/string/string_name.cpp b/core/string/string_name.cpp
index 11674629fc74..19539b1bccaa 100644
--- a/core/string/string_name.cpp
+++ b/core/string/string_name.cpp
@@ -30,8 +30,13 @@
 
 #include "string_name.h"
 
+#include <stdint.h>
+
+#include "core/error/error_macros.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
 #include "core/string/print_string.h"
+#include "core/templates/vector.h"
 
 StaticCString StaticCString::create(const char *p_ptr) {
 	StaticCString scs;
diff --git a/core/string/string_name.h b/core/string/string_name.h
index 9653d2b4cf89..c95c05e262d8 100644
--- a/core/string/string_name.h
+++ b/core/string/string_name.h
@@ -31,9 +31,12 @@
 #ifndef STRING_NAME_H
 #define STRING_NAME_H
 
+#include <cstdint>
+
 #include "core/os/mutex.h"
 #include "core/string/ustring.h"
 #include "core/templates/safe_refcount.h"
+#include "core/typedefs.h"
 
 class Main;
 
diff --git a/core/string/translation.cpp b/core/string/translation.cpp
index 7cc41df9efd7..590b2d84368c 100644
--- a/core/string/translation.cpp
+++ b/core/string/translation.cpp
@@ -30,10 +30,17 @@
 
 #include "translation.h"
 
+#include "core/config/engine.h"
 #include "core/config/project_settings.h"
+#include "core/error/error_macros.h"
 #include "core/io/resource_loader.h"
+#include "core/object/class_db.h"
+#include "core/os/main_loop.h"
 #include "core/os/os.h"
+#include "core/string/char_utils.h"
 #include "core/string/locales.h"
+#include "core/templates/pair.h"
+#include "core/variant/variant.h"
 
 #ifdef TOOLS_ENABLED
 #include "main/main.h"
diff --git a/core/string/translation.h b/core/string/translation.h
index 947ca4c6d817..2a32cf3f93e1 100644
--- a/core/string/translation.h
+++ b/core/string/translation.h
@@ -33,7 +33,18 @@
 
 #include "core/io/resource.h"
 #include "core/object/gdvirtual.gen.inc"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/map.h"
+#include "core/templates/set.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
 
 class Translation : public Resource {
 	GDCLASS(Translation, Resource);
diff --git a/core/string/translation_po.cpp b/core/string/translation_po.cpp
index 1c991ee12dbc..998396d810e6 100644
--- a/core/string/translation_po.cpp
+++ b/core/string/translation_po.cpp
@@ -30,7 +30,10 @@
 
 #include "translation_po.h"
 
-#include "core/io/file_access.h"
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
+#include "core/object/class_db.h"
+#include "core/variant/variant.h"
 
 #ifdef DEBUG_TRANSLATION_PO
 void TranslationPO::print_translation_map() {
diff --git a/core/string/translation_po.h b/core/string/translation_po.h
index 7d63af224690..7810fd528f9b 100644
--- a/core/string/translation_po.h
+++ b/core/string/translation_po.h
@@ -34,7 +34,16 @@
 //#define DEBUG_TRANSLATION_PO
 
 #include "core/math/expression.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/string_name.h"
 #include "core/string/translation.h"
+#include "core/string/ustring.h"
+#include "core/templates/hash_map.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
 
 class TranslationPO : public Translation {
 	GDCLASS(TranslationPO, Translation);
diff --git a/core/string/ustring.cpp b/core/string/ustring.cpp
index c4edc8c086d3..78744dc341f2 100644
--- a/core/string/ustring.cpp
+++ b/core/string/ustring.cpp
@@ -30,20 +30,27 @@
 
 #include "ustring.h"
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <cmath>
+#include <cstdint>
+
 #include "core/crypto/crypto_core.h"
+#include "core/error/error_macros.h"
 #include "core/math/color.h"
 #include "core/math/math_funcs.h"
-#include "core/os/memory.h"
+#include "core/string/char_utils.h"
 #include "core/string/print_string.h"
+#include "core/string/string_name.h"
 #include "core/string/translation.h"
 #include "core/string/ucaps.h"
+#include "core/templates/list.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
 #include "core/variant/variant.h"
 #include "core/version_generated.gen.h"
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <cstdint>
-
 #ifdef _MSC_VER
 #define _CRT_SECURE_NO_WARNINGS // to disable build-time warning which suggested to use strcpy_s instead strcpy
 #endif
diff --git a/core/string/ustring.h b/core/string/ustring.h
index 1d302b65a724..d7c7079ce5a0 100644
--- a/core/string/ustring.h
+++ b/core/string/ustring.h
@@ -32,12 +32,18 @@
 #define USTRING_GODOT_H
 // Note: Renamed to avoid conflict with ICU header with the same name.
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/string/char_utils.h"
 #include "core/templates/cowdata.h"
 #include "core/templates/vector.h"
 #include "core/typedefs.h"
 #include "core/variant/array.h"
 
+class Array;
+class Variant;
+
 /*************************************************************************/
 /*  CharProxy                                                            */
 /*************************************************************************/
diff --git a/core/templates/command_queue_mt.cpp b/core/templates/command_queue_mt.cpp
index a40ff88a194b..78531913aa91 100644
--- a/core/templates/command_queue_mt.cpp
+++ b/core/templates/command_queue_mt.cpp
@@ -30,7 +30,6 @@
 
 #include "command_queue_mt.h"
 
-#include "core/config/project_settings.h"
 #include "core/os/os.h"
 
 void CommandQueueMT::lock() {
diff --git a/core/templates/command_queue_mt.h b/core/templates/command_queue_mt.h
index 1ecb81c2a27f..48654be05dbe 100644
--- a/core/templates/command_queue_mt.h
+++ b/core/templates/command_queue_mt.h
@@ -31,6 +31,9 @@
 #ifndef COMMAND_QUEUE_MT_H
 #define COMMAND_QUEUE_MT_H
 
+#include <stdint.h>
+
+#include "core/error/error_macros.h"
 #include "core/os/memory.h"
 #include "core/os/mutex.h"
 #include "core/os/semaphore.h"
diff --git a/core/templates/rid_owner.cpp b/core/templates/rid_owner.cpp
index 7fc819e232e8..f07540d8f353 100644
--- a/core/templates/rid_owner.cpp
+++ b/core/templates/rid_owner.cpp
@@ -30,4 +30,6 @@
 
 #include "rid_owner.h"
 
+#include <cstdint>
+
 SafeNumeric<uint64_t> RID_AllocBase::base_id{ 1 };
diff --git a/core/templates/rid_owner.h b/core/templates/rid_owner.h
index 95632cdec242..eb16f9183d78 100644
--- a/core/templates/rid_owner.h
+++ b/core/templates/rid_owner.h
@@ -31,17 +31,21 @@
 #ifndef RID_OWNER_H
 #define RID_OWNER_H
 
+#include <stdint.h>
+#include <stdio.h>
+#include <typeinfo>
+
+#include "core/error/error_macros.h"
 #include "core/os/memory.h"
 #include "core/os/spin_lock.h"
 #include "core/string/print_string.h"
+#include "core/string/ustring.h"
 #include "core/templates/list.h"
 #include "core/templates/oa_hash_map.h"
 #include "core/templates/rid.h"
 #include "core/templates/safe_refcount.h"
 #include "core/templates/set.h"
-
-#include <stdio.h>
-#include <typeinfo>
+#include "core/typedefs.h"
 
 class RID_AllocBase {
 	static SafeNumeric<uint64_t> base_id;
diff --git a/core/templates/thread_work_pool.h b/core/templates/thread_work_pool.h
index 957af44f48ac..248878d2e73b 100644
--- a/core/templates/thread_work_pool.h
+++ b/core/templates/thread_work_pool.h
@@ -31,11 +31,14 @@
 #ifndef THREAD_WORK_POOL_H
 #define THREAD_WORK_POOL_H
 
+#include <stdint.h>
+#include <atomic>
+
+#include "core/error/error_macros.h"
 #include "core/os/memory.h"
 #include "core/os/semaphore.h"
 #include "core/os/thread.h"
-
-#include <atomic>
+#include "core/typedefs.h"
 
 class ThreadWorkPool {
 	std::atomic<uint32_t> index;
diff --git a/core/variant/array.cpp b/core/variant/array.cpp
index 1b39558dff92..a17175fc0725 100644
--- a/core/variant/array.cpp
+++ b/core/variant/array.cpp
@@ -31,10 +31,17 @@
 #include "array.h"
 
 #include "container_type_validate.h"
-#include "core/object/class_db.h"
+#include "core/error/error_macros.h"
+#include "core/math/math_funcs.h"
+#include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/os/memory.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
 #include "core/templates/hashfuncs.h"
+#include "core/templates/safe_refcount.h"
 #include "core/templates/search_array.h"
+#include "core/templates/sort_array.h"
 #include "core/templates/vector.h"
 #include "core/variant/callable.h"
 #include "core/variant/variant.h"
diff --git a/core/variant/array.h b/core/variant/array.h
index 72bed5932c4b..8cfbe06ee299 100644
--- a/core/variant/array.h
+++ b/core/variant/array.h
@@ -31,10 +31,12 @@
 #ifndef ARRAY_H
 #define ARRAY_H
 
-#include "core/typedefs.h"
-
+#include <stdint.h>
 #include <climits>
 
+#include "core/error/error_list.h"
+#include "core/typedefs.h"
+
 class Variant;
 class ArrayPrivate;
 class Object;
diff --git a/core/variant/callable.cpp b/core/variant/callable.cpp
index c6a67f01d54f..e76ffb60ef82 100644
--- a/core/variant/callable.cpp
+++ b/core/variant/callable.cpp
@@ -31,10 +31,16 @@
 #include "callable.h"
 
 #include "callable_bind.h"
+#include "core/error/error_macros.h"
 #include "core/object/message_queue.h"
 #include "core/object/object.h"
 #include "core/object/ref_counted.h"
 #include "core/object/script_language.h"
+#include "core/os/memory.h"
+#include "core/templates/hashfuncs.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/variant/variant.h"
 
 void Callable::call_deferred(const Variant **p_arguments, int p_argcount) const {
 	MessageQueue::get_singleton()->push_callable(*this, p_arguments, p_argcount);
diff --git a/core/variant/callable.h b/core/variant/callable.h
index 855ffa912941..659e2c579e75 100644
--- a/core/variant/callable.h
+++ b/core/variant/callable.h
@@ -31,9 +31,16 @@
 #ifndef CALLABLE_H
 #define CALLABLE_H
 
+#include <stdint.h>
+
+#include "core/error/error_list.h"
 #include "core/object/object_id.h"
 #include "core/string/string_name.h"
+#include "core/string/ustring.h"
 #include "core/templates/list.h"
+#include "core/templates/safe_refcount.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
 
 class Object;
 class Variant;
diff --git a/core/variant/callable_bind.h b/core/variant/callable_bind.h
index ac5797e05f65..85cc8f8b6dd2 100644
--- a/core/variant/callable_bind.h
+++ b/core/variant/callable_bind.h
@@ -31,6 +31,11 @@
 #ifndef CALLABLE_BIND_H
 #define CALLABLE_BIND_H
 
+#include <stdint.h>
+
+#include "core/object/object_id.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
 #include "core/variant/callable.h"
 #include "core/variant/variant.h"
 
diff --git a/core/variant/dictionary.cpp b/core/variant/dictionary.cpp
index 0f2f8fc8ed14..7e99aec107f4 100644
--- a/core/variant/dictionary.cpp
+++ b/core/variant/dictionary.cpp
@@ -30,9 +30,14 @@
 
 #include "dictionary.h"
 
+#include "core/error/error_macros.h"
+#include "core/os/memory.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/hashfuncs.h"
 #include "core/templates/ordered_hash_map.h"
 #include "core/templates/safe_refcount.h"
-#include "core/variant/variant.h"
+#include "core/typedefs.h"
 // required in this order by VariantInternal, do not remove this comment.
 #include "core/object/class_db.h"
 #include "core/object/object.h"
diff --git a/core/variant/dictionary.h b/core/variant/dictionary.h
index 16cf0c2bf89a..90c4792eced7 100644
--- a/core/variant/dictionary.h
+++ b/core/variant/dictionary.h
@@ -31,12 +31,13 @@
 #ifndef DICTIONARY_H
 #define DICTIONARY_H
 
+#include <stdint.h>
+
 #include "core/string/ustring.h"
 #include "core/templates/list.h"
 #include "core/variant/array.h"
 
 class Variant;
-
 struct DictionaryPrivate;
 
 class Dictionary {
diff --git a/core/variant/variant.cpp b/core/variant/variant.cpp
index fcfa5303889e..0d8aa3ab5ff7 100644
--- a/core/variant/variant.cpp
+++ b/core/variant/variant.cpp
@@ -32,11 +32,14 @@
 
 #include "core/core_string_names.h"
 #include "core/debugger/engine_debugger.h"
+#include "core/error/error_macros.h"
 #include "core/io/json.h"
-#include "core/io/marshalls.h"
 #include "core/io/resource.h"
+#include "core/math/face3.h"
 #include "core/math/math_funcs.h"
-#include "core/string/print_string.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/templates/hashfuncs.h"
 #include "core/variant/variant_parser.h"
 
 String Variant::get_type_name(Variant::Type p_type) {
diff --git a/core/variant/variant.h b/core/variant/variant.h
index b75882a87c41..5c1187733312 100644
--- a/core/variant/variant.h
+++ b/core/variant/variant.h
@@ -31,12 +31,15 @@
 #ifndef VARIANT_H
 #define VARIANT_H
 
+#include <stdint.h>
+
 #include "core/input/input_enums.h"
 #include "core/io/ip_address.h"
 #include "core/math/aabb.h"
 #include "core/math/basis.h"
 #include "core/math/color.h"
 #include "core/math/face3.h"
+#include "core/math/math_defs.h"
 #include "core/math/plane.h"
 #include "core/math/quaternion.h"
 #include "core/math/rect2.h"
@@ -47,19 +50,26 @@
 #include "core/math/vector2i.h"
 #include "core/math/vector3.h"
 #include "core/math/vector3i.h"
+
 #include "core/object/object_id.h"
 #include "core/os/keyboard.h"
+#include "core/os/memory.h"
 #include "core/string/node_path.h"
+#include "core/string/string_name.h"
 #include "core/string/ustring.h"
+#include "core/templates/list.h"
 #include "core/templates/rid.h"
+#include "core/templates/safe_refcount.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
 #include "core/variant/array.h"
 #include "core/variant/callable.h"
 #include "core/variant/dictionary.h"
 
 class Object;
-
 struct PropertyInfo;
 struct MethodInfo;
+struct Face3;
 
 typedef Vector<uint8_t> PackedByteArray;
 typedef Vector<int32_t> PackedInt32Array;
diff --git a/core/variant/variant_call.cpp b/core/variant/variant_call.cpp
index 750f23902d70..66e075b3aa9f 100644
--- a/core/variant/variant_call.cpp
+++ b/core/variant/variant_call.cpp
@@ -28,17 +28,56 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
+#include <limits.h>
+#include <math.h>
+#include <stdint.h>
+#include <string.h>
+
 #include "variant.h"
 
-#include "core/core_string_names.h"
-#include "core/crypto/crypto_core.h"
 #include "core/debugger/engine_debugger.h"
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
 #include "core/io/compression.h"
 #include "core/io/marshalls.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/math_defs.h"
+#include "core/math/math_funcs.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
 #include "core/object/class_db.h"
-#include "core/os/os.h"
+#include "core/object/method_bind.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
+#include "core/os/memory.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/hashfuncs.h"
+#include "core/templates/list.h"
 #include "core/templates/local_vector.h"
+#include "core/templates/map.h"
 #include "core/templates/oa_hash_map.h"
+#include "core/templates/rid.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/method_ptrcall.h"
+#include "core/variant/type_info.h"
+#include "core/variant/variant_internal.h"
 
 typedef void (*VariantFunc)(Variant &r_ret, Variant &p_self, const Variant **p_args);
 typedef void (*VariantConstructFunc)(Variant &r_ret, const Variant **p_args);
diff --git a/core/variant/variant_construct.cpp b/core/variant/variant_construct.cpp
index 351f4ae253b2..2526aba449df 100644
--- a/core/variant/variant_construct.cpp
+++ b/core/variant/variant_construct.cpp
@@ -30,6 +30,13 @@
 
 #include "variant_construct.h"
 
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/templates/list.h"
+#include "core/templates/local_vector.h"
+#include "core/templates/vector.h"
+#include "core/variant/variant.h"
+
 struct VariantConstructData {
 	void (*construct)(Variant &r_base, const Variant **p_args, Callable::CallError &r_error);
 	Variant::ValidatedConstructor validated_construct;
diff --git a/core/variant/variant_construct.h b/core/variant/variant_construct.h
index 6027cb027ee3..1d7ff029d2a1 100644
--- a/core/variant/variant_construct.h
+++ b/core/variant/variant_construct.h
@@ -31,16 +31,50 @@
 #ifndef VARIANT_CONSTRUCT_H
 #define VARIANT_CONSTRUCT_H
 
-#include "variant.h"
+#include <stddef.h>
+#include <stdint.h>
 
 #include "core/core_string_names.h"
 #include "core/crypto/crypto_core.h"
 #include "core/debugger/engine_debugger.h"
+#include "core/error/error_macros.h"
 #include "core/io/compression.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
 #include "core/object/class_db.h"
+#include "core/object/object_id.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
 #include "core/templates/local_vector.h"
 #include "core/templates/oa_hash_map.h"
+#include "core/templates/rid.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/binder_common.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/method_ptrcall.h"
+#include "core/variant/type_info.h"
+#include "core/variant/variant_internal.h"
+#include "variant.h"
+
+class Object;
+template <class T>
+struct PtrConstruct;
 
 template <class T>
 struct PtrConstruct {};
diff --git a/core/variant/variant_destruct.cpp b/core/variant/variant_destruct.cpp
index ab8303f3aeeb..4df446d8614e 100644
--- a/core/variant/variant_destruct.cpp
+++ b/core/variant/variant_destruct.cpp
@@ -30,7 +30,7 @@
 
 #include "variant_destruct.h"
 
-#include "core/templates/local_vector.h"
+#include "core/error/error_macros.h"
 
 static Variant::PTRDestructor destruct_pointers[Variant::VARIANT_MAX] = { nullptr };
 
diff --git a/core/variant/variant_destruct.h b/core/variant/variant_destruct.h
index 5e3478635ded..716f9f3ed427 100644
--- a/core/variant/variant_destruct.h
+++ b/core/variant/variant_destruct.h
@@ -31,9 +31,24 @@
 #ifndef VARIANT_DESTRUCT_H
 #define VARIANT_DESTRUCT_H
 
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/object/class_db.h"
+#include "core/string/node_path.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/rid.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/type_info.h"
 #include "core/variant/variant.h"
 
-#include "core/object/class_db.h"
+template <class T>
+struct VariantDestruct;
 
 template <class T>
 struct VariantDestruct {};
diff --git a/core/variant/variant_internal.h b/core/variant/variant_internal.h
index aaafa2f6b6be..96c708e7c317 100644
--- a/core/variant/variant_internal.h
+++ b/core/variant/variant_internal.h
@@ -33,6 +33,8 @@
 
 #include "variant.h"
 
+#include "core/object/object.h"
+
 // For use when you want to access the internal pointer of a Variant directly.
 // Use with caution. You need to be sure that the type is correct.
 class VariantInternal {
diff --git a/core/variant/variant_op.cpp b/core/variant/variant_op.cpp
index f35774204bcd..1ad89e25389a 100644
--- a/core/variant/variant_op.cpp
+++ b/core/variant/variant_op.cpp
@@ -30,6 +30,24 @@
 
 #include "variant_op.h"
 
+#include <string.h>
+
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector3.h"
+#include "core/string/node_path.h"
+#include "core/templates/rid.h"
+#include "core/variant/callable.h"
+#include "core/variant/variant.h"
+
 typedef void (*VariantEvaluatorFunction)(const Variant &p_left, const Variant &p_right, Variant *r_ret, bool &r_valid);
 
 static Variant::Type operator_return_type_table[Variant::OP_MAX][Variant::VARIANT_MAX][Variant::VARIANT_MAX];
diff --git a/core/variant/variant_op.h b/core/variant/variant_op.h
index f72a92d31a3c..45b45788e651 100644
--- a/core/variant/variant_op.h
+++ b/core/variant/variant_op.h
@@ -31,11 +31,25 @@
 #ifndef VARIANT_OP_H
 #define VARIANT_OP_H
 
-#include "variant.h"
+#include <stdint.h>
 
 #include "core/core_string_names.h"
 #include "core/debugger/engine_debugger.h"
+#include "core/error/error_macros.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3i.h"
 #include "core/object/class_db.h"
+#include "core/object/object.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/method_ptrcall.h"
+#include "core/variant/type_info.h"
+#include "core/variant/variant_internal.h"
+#include "variant.h"
 
 template <class R, class A, class B>
 class OperatorEvaluatorAdd {
diff --git a/core/variant/variant_parser.cpp b/core/variant/variant_parser.cpp
index e889a1bb40af..67e14347a7eb 100644
--- a/core/variant/variant_parser.cpp
+++ b/core/variant/variant_parser.cpp
@@ -30,10 +30,38 @@
 
 #include "variant_parser.h"
 
-#include "core/input/input_event.h"
+#include <stdint.h>
+#include <cmath>
+
+#include "core/error/error_macros.h"
+#include "core/io/file_access.h"
 #include "core/io/resource_loader.h"
-#include "core/os/keyboard.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/math_defs.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
+#include "core/object/class_db.h"
+#include "core/object/object.h"
+#include "core/object/ref_counted.h"
+#include "core/string/char_utils.h"
+#include "core/string/node_path.h"
 #include "core/string/string_buffer.h"
+#include "core/string/string_name.h"
+#include "core/templates/list.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/dictionary.h"
 
 char32_t VariantParser::StreamFile::get_char() {
 	return f->get_8();
diff --git a/core/variant/variant_parser.h b/core/variant/variant_parser.h
index e5585076c213..3028dfbbdc55 100644
--- a/core/variant/variant_parser.h
+++ b/core/variant/variant_parser.h
@@ -31,10 +31,21 @@
 #ifndef VARIANT_PARSER_H
 #define VARIANT_PARSER_H
 
+#include "core/error/error_list.h"
 #include "core/io/file_access.h"
 #include "core/io/resource.h"
+#include "core/string/ustring.h"
+#include "core/templates/map.h"
 #include "core/variant/variant.h"
 
+class Array;
+class Dictionary;
+class FileAccess;
+template <class T>
+class Ref;
+template <class T>
+class Vector;
+
 class VariantParser {
 public:
 	struct Stream {
diff --git a/core/variant/variant_setget.cpp b/core/variant/variant_setget.cpp
index fa8d26a72b0c..7af73d38fa57 100644
--- a/core/variant/variant_setget.cpp
+++ b/core/variant/variant_setget.cpp
@@ -30,6 +30,23 @@
 
 #include "variant_setget.h"
 
+#include "core/core_string_names.h"
+#include "core/debugger/engine_debugger.h"
+#include "core/error/error_macros.h"
+#include "core/math/math_defs.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/list.h"
+#include "core/templates/local_vector.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
+#include "core/variant/array.h"
+#include "core/variant/callable.h"
+#include "core/variant/dictionary.h"
+#include "core/variant/variant.h"
+
 struct VariantSetterGetterInfo {
 	void (*setter)(Variant *base, const Variant *value, bool &valid);
 	void (*getter)(const Variant *base, Variant *value);
diff --git a/core/variant/variant_setget.h b/core/variant/variant_setget.h
index 28277fa5d0e8..1154083c9e78 100644
--- a/core/variant/variant_setget.h
+++ b/core/variant/variant_setget.h
@@ -31,13 +31,29 @@
 #ifndef VARIANT_SETGET_H
 #define VARIANT_SETGET_H
 
-#include "variant.h"
+#include <stdint.h>
 
 #include "core/core_string_names.h"
 #include "core/debugger/engine_debugger.h"
+#include "core/math/aabb.h"
+#include "core/math/basis.h"
+#include "core/math/color.h"
+#include "core/math/plane.h"
+#include "core/math/quaternion.h"
+#include "core/math/rect2.h"
+#include "core/math/rect2i.h"
+#include "core/math/transform_2d.h"
+#include "core/math/transform_3d.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
 #include "core/object/class_db.h"
 #include "core/templates/local_vector.h"
+#include "core/variant/method_ptrcall.h"
+#include "core/variant/type_info.h"
 #include "core/variant/variant_internal.h"
+#include "variant.h"
 
 /**** NAMED SETTERS AND GETTERS ****/
 
diff --git a/core/variant/variant_utility.cpp b/core/variant/variant_utility.cpp
index 60950099d2d7..373515e0b924 100644
--- a/core/variant/variant_utility.cpp
+++ b/core/variant/variant_utility.cpp
@@ -28,17 +28,40 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#include "variant.h"
+#include <stddef.h>
+#include <stdint.h>
 
-#include "core/core_string_names.h"
+#include "core/error/error_list.h"
+#include "core/error/error_macros.h"
 #include "core/io/marshalls.h"
+#include "core/math/math_funcs.h"
+#include "core/math/vector2.h"
+#include "core/math/vector2i.h"
+#include "core/math/vector3.h"
+#include "core/math/vector3i.h"
+#include "core/object/method_bind.h"
+#include "core/object/object.h"
+#include "core/object/object_id.h"
 #include "core/object/ref_counted.h"
+#include "core/os/memory.h"
 #include "core/os/os.h"
+#include "core/string/print_string.h"
+#include "core/string/string_name.h"
+#include "core/string/ustring.h"
+#include "core/templates/hashfuncs.h"
+#include "core/templates/list.h"
 #include "core/templates/oa_hash_map.h"
 #include "core/templates/rid.h"
 #include "core/templates/rid_owner.h"
+#include "core/templates/vector.h"
+#include "core/typedefs.h"
 #include "core/variant/binder_common.h"
+#include "core/variant/callable.h"
+#include "core/variant/method_ptrcall.h"
+#include "core/variant/type_info.h"
+#include "core/variant/variant_internal.h"
 #include "core/variant/variant_parser.h"
+#include "variant.h"
 
 struct VariantUtilityFunctions {
 	// Math