Epics: Deacon, Uugo, Farahkin are all useful all the way through to end-game content.

Legos: Valkyrie & Yncensa

I did farahkin, maybe yncensa next! Thank you for the recommendation. He definitely raised my CB damage up a few mil

More importantly, you have Wixwell. Which means you can very easily build a UNM CB team that can do 100M+ dmg per key. Look up some guides, but the tl;dr is Wixwell + 2 buff extenders = easy win.

Yncensa or Vulkanos. Also Uugo and Firrol.

Also If you can expand your roster horizontally we can see more, there's a few leggos there that are clipped off from good visibility. 

Vulkanos can do really high damage against CB but you need to turn off his A2. His A1 and A3 are insane. Heck if you pair him with Yncensa and he's got the highest crit dmg, he's gotta do SO MUCH more to CB plus despite him being Faction Unity, you can bring him as the only Demon (based on your current roster) to CB and he's still great. You'll want to pair him with Ninja most likely for CB. 

Firrol 1000% for Hydra.  Probably best Hydra support champ in the game.