This is four months old, but is copy paste from Mike Dilger himself...

Gossip, coracle, nozzle, camelus.app, snort, lume, amethyst, and anything built using PABLOF7Zs NDK use this NIP-65 "gossip model".

Damus, primal, iris, and many other clients still use a fixed set of relays, many with a client-side caching server so their users don't miss out of notes on other relays. But most of those client's developers have expressed interest or concrete plans to move to the gossip model. Rabble just mentioned today that is on the roadmap for nos.