This is the Trump N’Zoth Priest w Onyx Bishop Barnes Deck he was playing on stream. The new card Onyx Bishop has brought new life to the Priest class.
It also has N’Zoth at the top end for a solid win condition. You have Sylvanas, Cairne Bloodhoof, and Shifting Shades to bring back from the graveyard.
Priest has a really strong midgame now with Priest of the Feast healing them. It’s not too hard to make it to the late game, even vs aggro. I’m not sure if I like the Moroes in this deck, but it was working out for Trump so it can’t be that bad.
General Mulligan Strategy for Onyx Bishop Priest
Look for Northshire Cleric and removal spells like Shadow Word: Death, and Shadow Word: Pain. You want to protect your Cleric and draw as much as possible early on.