Yeah. Also there's Ricochet and its continuation Ricochet Refresh, but these only do 1:1 messaging AFAIK.[1][2]

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/