* :heavy_check_mark: [Prismo](https://gitlab.com/mbajur/prismo) contact at [@prismo](https://mastodon.social/@prismo)
* :black_nib: [Smilodon](https://source.puri.sm/liberty/host/smilodon/) - the server by Purism used in LibreOne, not the abandoned Tuxcraft server or Pylodon client. "A complementary fork of Mastodon, focusing on opt-in public spaces."
Note: Friendica (see above) has a groups engine but there are no reports that federation of groups over AP is working yet