Over on the Help site Todd asked about creating special collection pages:

I’d like to create special collection pages that do the following.

  1. Let me create a custom section of content at the top. (think: intro, description, maybe some links or disclaimers)
  2. Automated collection of posts with a certain tag. Preferably with options for me on how to display (alphabetical, chronoligical, reverse-chronological, etc.)

There's a detailed answer that begins:

My favorite way to do this is to make a custom layout like:

layouts/thepagename/list.html

Then I put my template there