Eleventy lets you gather items together into collections in a variety of ways. I regularly want to have a set of blog posts so ElevenTail is set up with a collection of posts held in a blog folder.
Posts are markdown files, but could be any other formats supported by Eleventy. And a custom plugin written in JavaScript gives access to the content of the post before and after an excerpt delimiter so that they can be styled differently like this.
This page is part of the blog section.