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.
Do people actually look at the temperature to deterimne how to dress? For me a calendar is far more useful. And i can stick my head out the door to confirm if i need an extra layer…