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.
Ask someone in the north of finland how hot is “very hot”, and how cold is very cold. Then ask the same in middle Africa. Spoiler: it will vary alot.