Over the years I've gotten used to reading code with syntax highlighting. The colouring of the highlighting provides anchoring points for my eyes as I scroll, helping me to keep my place. However, when I'd be editing plain-text, I have no anchoring points, just a huge wall of text; so I wrote a simple syntax file for it.
All it does is highlights capitalized words, very simple. This typically ends up highlighting things of importance: headings, names, and most importantly the beginning of sentences. I've found this to be a good amount of highlighting without being overwhelming, providing context without being overly flashy.
Here's my current version:
