Just Pear Credit, but thanks for adding to the list ;-).

5. Holepunch

VDO.Ninja uses websockets, as does Nostr, but there is no reliance on a relay server -- just a handshake server which opens the websockets connection directly between you and your peer(s) web browser.

It's completely anonymous, as in no public keys or unique identifiers. Which reminds me!

6. https://simplex.chat a Direct Messenger without User IDs (!) that appears even more secure than Session. You'll need Android 10+ to run the Android app, haven't tried the iOS app.