There are a couple I have in mind. Like many techies, I am a huge fan of RSS for content distribution and XMPP for federated communication.
The really niche one I like is S-expressions as a data format and configuration in place of json, yaml, toml, etc.
I am a big fan of Plaintext formats, although I wish markdown had a few more features like tables.
The content of the feed depends on the content creator, not on RSS.
I know that. But RSS is like 95% used for news feeds and that’s what I’m talking about. The way RSS is overwhelmingly used is making the whole thing useless (to me).