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.
JSON5. it’s basically just JSON with several QoL improvements, like comments, that make it usable as a format for human consumption (as opposed to a serialization format).
I just came.
TMI
TIL this exists