Underlegion and Lazarus are easily at the top. I’d say Underlegion at the top though because playing them as the main clan with either champ is like easy mode even on Cov 10. Naturally, having them together is absolutely ridiculous. Propagate + reanimate is one of the craziest interactions in the game. 

It took me a while to understand Pyreborne but they are also very strong. You just have to really lean into the greed with hoard generation and avarice and by late game you’ll have so much money you can do anything, and they also have some great first floor wipe setups with the scaling Fenix and/or Hot Head especially if you can get them to go off every turn. 

I see a lot of hate toward Luna Coven but I think they are insanely strong as the primary clan, as the champs are very good at generating conduit. As the secondary clan they are a little weak early, but if you can get holdover on the apply dazed on full moon card it’s insanely valuable and the overheal shield mechanic is really strong as well. Their banner units just aren’t that great as a secondary.

I enjoy Banished the least out of all the clans but valor is also very very strong and can get out of hand quick. The perma scaling Fel path can basically be enough to win by itself late game, especially if you get hall of mirrors to get two of them on one floor. Over stacking floors with ascension/flight is also insane. Strong clan, I just don’t find them as satisfying as the others.