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 semantic web and social linked data. We could have applications share data without depending on big tech, but rather based on application standards.
It can be used today and gains traction but I wouldn’t mind it going faster. Especially the interoperable personal app space could use some love and attention.