Sentinel is a great toss in tank for any All Melee battle, paired with Mylor for Thorns, he is REALLY strong.
He's also good for low mana No Melee battles as a cheap tank if you can't afford the Giant!

Cornealus is so so strong honestly. I get my butt kicked by him all the time in low Mana AND high mana. He doesn't seem like it'd work in low mana but his heal is really that strong.
The most important thing is to have him in the back position with enough cannon fodder protecting him. (He's also super good in Earthquake/Poison rounds!)