I'd just use Pandoc Markdown. For simple things, you can easily write Markdown that is compatible with all dialects. Mainly, remember to indent your lists 4 sp

I'd just use Pandoc Markdown. For simple things, you can easily write Markdown that is compatible with all dialects. Mainly, remember to indent your lists 4 spaces if you soft wrap. But Pandoc Markdown has the most extensive support for other extensions, like footnotes, figures, etc. That's useful because it minimizes how much HTML or Latex you need to write, which in turn makes your documents more portable. There are other formats that support more features, but in my experience the communities are smaller and the syntax is not as pretty. Ultimately you're betting on that format continuing to exist longer than Pandoc, which I think is not a great bet in most cases. The only format which I think might have better long-term support and compatibility is CommonMark, but it comes at the tradeoff of substantially fewer features. Which again means sacrificing portability because everything you can't do in the base language you need to do in HTML or Latex.