@jakehamilton I'm an obsessive self hoster, and have been filling the gaps of my stack where things have been missing.
For the most part, in recent years, this translates to HTTP(S) crawler defense, in the form of iocaine. More recently (as of this morning), I'm also working on a milter, aiming to replace rspamd (which is slop-infected, and a pain in the ass to configure anyway), in a similar spirit to (and reusing parts of) iocaine.
I'm interested in pretty much anything related to self hosting, and making that easier. Like, I wrote a small howto on running Prosody in my homelab, behind a Wireguard tunnel, while still allowing voice & video calls from external networks (by running a STUN/TURN server on the fronting VPS).
If there was such a collective, I'd continue working on crawler/spam defense, and writing documentation about how to self-host this and that without relying on The Cloud™ too much.