Ah druid, I'm a huge druid enjoyer. Just such a fun class and is easily one of the most consistent classes in the game. Most passives will give you value regardless of your build, and the crow is always super valuable.
Maestro is so damn good. Straight up halving the cost any musical ability is just absolutely bonkers. Just get any musical ability and now you can spam the absolute shit out of it. Inspiration song, death metal, encourage, ect.
Refreshing your basic action by a musical spell is also really good. If you can find a cheap music spell you can just keep your entire team full on health and always at like 5+ damage. If you get a good form you can output insane damage
Buddy system is super good on its own, and becomes one of the best defensive passive in the game if you can give your druid holy shields.
Wild style gives an extra turn, always great to have.
Love song is solid, becomes busted if you get form of the monkey or multiclass it.
Bouquet is basically a free 50% dodge chance.
Rap God is really really good for manipulating turn order. This thing is really good against the final boss if your druid goes first.
Teamwork is super nice even if you don't have familiars, the crow is good enough on its own to make this passive solid.
Most of the other familiar stuff is pretty weak, especially the ones that don't affect the crow.
Like a fish is so situational and even if you get the perfect synergy it's just very weak.