This blog plugin allows for a new header attribute of published to be set to either True or False. If False the post will not be added to the generated post list. Just drop blog.py into the plugins/ directory.
An example post header might be:
title: Best Post Ever
headline: There has never been a post better than this!
author: Devin
date: 26-02-2017
published: True
A post with published false can still be accessed with the direct URL.
title: Another Great Post
headline: But this post isn't ready for the public!
author: Devin
date: 26-02-2017
published: False