This is a list of federated social clients and other related tools that use protocols other than those used in the fediverse (OStatus, ActivityPub, Diaspora, DFRN, Zot)
The blockchain social apps list has its own page, because although all these apps are distributed in some way (because they use a blockchain), they're not all federated with anything other than other copies of their own app.
Matrix is a federated web protocol, used mainly so far for realtime chat rooms.
Patchworkis an SSB client for desktop platforms (currently supporting GNU/Linux, MacOS, and Windows).
Movim is a web client with social network features, written in PHP and uses eJabberd (Erlang) backend any XMPP server with XEP-0060 PubSub support. Users can login to any Movim instance using any XMPP account, just as they can login to any Pinafore instance using any Mastodon account.
Salut à Toi (includes the Libervia web client) is a social network based on XMPP/Jabber.