Ricochet was a big inspiration for my project Quiet.[3]
Cwtch also deserves a mention, though it depends on ephemeral servers and isn't fully p2p. Briar is another and frequently comes up on HN. [4][5]
1. https://en.wikipedia.org/wiki/Ricochet_(software)
2. https://www.ricochetrefresh.net/
3. https://tryquiet.org/
4. https://cwtch.im/
5. https://briarproject.org/
