There is a project working on shared & real-time updated block-lists (and a chain of trust model) that originated from within the Lemmy community: https://fediseer.com/

It was set up pre-emptively last year when automated bot accounts were exploding, but somehow that never turned into much spam. But the infrastructure is there now and basically waits for a real-world test case.

There are also several auto-moderation bot frameworks, such as Threativore which we have running here on SLRPNK and which is planned to be integrated with Fediseer as well.

XMPP also has a similar concept with https://xmppbl.org/ and IRC had a similar system for spam IPs for a long time.