diff --git a/__tests__/spec-only.js b/__tests__/spec-only.js
index ea93a378..e54f1860 100644
--- a/__tests__/spec-only.js
+++ b/__tests__/spec-only.js
@@ -9,7 +9,13 @@ ruleTester.run('spec-only', rule, {
     'Promise.resolve()',
     'Promise.reject()',
     'Promise.all()',
+    'Promise["all"]',
+    'Promise[method];',
+    'Promise.prototype;',
+    'Promise.prototype[method];',
+    'Promise.prototype["then"];',
     'Promise.race()',
+    'var ctch = Promise.prototype.catch',
     'Promise.withResolvers()',
     'new Promise(function (resolve, reject) {})',
     'SomeClass.resolve()',
@@ -22,6 +28,14 @@ ruleTester.run('spec-only', rule, {
         },
       ],
     },
+    {
+      code: 'Promise.prototype.permittedInstanceMethod',
+      options: [
+        {
+          allowedMethods: ['permittedInstanceMethod'],
+        },
+      ],
+    },
   ],
   invalid: [
     {
@@ -53,5 +67,13 @@ ruleTester.run('spec-only', rule, {
       `,
       errors: [{ message: "Avoid using non-standard 'Promise.done'" }],
     },
+    {
+      code: `var done = Promise.prototype.done`,
+      errors: [{ message: "Avoid using non-standard 'Promise.prototype'" }],
+    },
+    {
+      code: `Promise["done"];`,
+      errors: [{ message: "Avoid using non-standard 'Promise.done'" }],
+    },
   ],
 })
diff --git a/rules/lib/is-promise.js b/rules/lib/is-promise.js
index 840dfb2f..a13f2bb7 100644
--- a/rules/lib/is-promise.js
+++ b/rules/lib/is-promise.js
@@ -29,7 +29,7 @@ function isPromise(expression) {
       expression.callee.type === 'MemberExpression' &&
       expression.callee.object.type === 'Identifier' &&
       expression.callee.object.name === 'Promise' &&
-      PROMISE_STATICS[expression.callee.property.name] &&
+      PROMISE_STATICS.has(expression.callee.property.name) &&
       expression.callee.property.name !== 'withResolvers')
   )
 }
diff --git a/rules/lib/promise-statics.js b/rules/lib/promise-statics.js
index e42205a0..3cf7415f 100644
--- a/rules/lib/promise-statics.js
+++ b/rules/lib/promise-statics.js
@@ -1,11 +1,11 @@
 'use strict'
 
-module.exports = {
-  all: true,
-  allSettled: true,
-  any: true,
-  race: true,
-  reject: true,
-  resolve: true,
-  withResolvers: true,
-}
+module.exports = new Set([
+  'all',
+  'allSettled',
+  'any',
+  'race',
+  'reject',
+  'resolve',
+  'withResolvers',
+])
diff --git a/rules/no-new-statics.js b/rules/no-new-statics.js
index c2483ce4..5274fe2e 100644
--- a/rules/no-new-statics.js
+++ b/rules/no-new-statics.js
@@ -22,7 +22,7 @@ module.exports = {
         if (
           node.callee.type === 'MemberExpression' &&
           node.callee.object.name === 'Promise' &&
-          PROMISE_STATICS[node.callee.property.name]
+          PROMISE_STATICS.has(node.callee.property.name)
         ) {
           context.report({
             node,
diff --git a/rules/spec-only.js b/rules/spec-only.js
index e5ab90a9..4554e3cc 100644
--- a/rules/spec-only.js
+++ b/rules/spec-only.js
@@ -3,6 +3,30 @@
 const PROMISE_STATICS = require('./lib/promise-statics')
 const getDocsUrl = require('./lib/get-docs-url')
 
+const PROMISE_INSTANCE_METHODS = new Set(['then', 'catch', 'finally'])
+
+function isPermittedProperty(expression, standardSet, allowedMethods) {
+  // istanbul ignore if
+  if (expression.type !== 'MemberExpression') return false
+
+  if (expression.property.type === 'Literal')
+    return (
+      standardSet.has(expression.property.value) ||
+      allowedMethods.includes(expression.property.value)
+    )
+
+  // istanbul ignore else
+  if (expression.property.type === 'Identifier')
+    return (
+      expression.computed ||
+      standardSet.has(expression.property.name) ||
+      allowedMethods.includes(expression.property.name)
+    )
+
+  // istanbul ignore next
+  return false
+}
+
 module.exports = {
   meta: {
     type: 'problem',
@@ -36,13 +60,20 @@ module.exports = {
         if (
           node.object.type === 'Identifier' &&
           node.object.name === 'Promise' &&
-          !(node.property.name in PROMISE_STATICS) &&
-          !allowedMethods.includes(node.property.name)
+          ((node.property.name !== 'prototype' &&
+            !isPermittedProperty(node, PROMISE_STATICS, allowedMethods)) ||
+            (node.property.name === 'prototype' &&
+              node.parent.type === 'MemberExpression' &&
+              !isPermittedProperty(
+                node.parent,
+                PROMISE_INSTANCE_METHODS,
+                allowedMethods,
+              )))
         ) {
           context.report({
             node,
             messageId: 'avoidNonStandard',
-            data: { name: node.property.name },
+            data: { name: node.property.name ?? node.property.value },
           })
         }
       },