Hearthpwn

For sure works, and if you get lucky with your other treasures, can trivialise runs.

I just won a heroic run by getting lucky and having barman Bob add 3 extra copies of Murgatha into my deck... twice. Plus some other treasures and spells I could clone extra ones from, and always started with one in my starting hand. I had 7 Murgatha's in my deck + multiple cloning spells.

As soon as turn 3 rolled around I'd start dropping mass murgathas, and then keep the enemy overloaded to 2 mana or less for the rest of the game.

On the final boss I ended up with 5 Murgatha's on the board, and as long as I could play at least two cards a turn (harder than it sounds when you have a full board!) I was keeping the enemy boss on 0 mana and it couldn't play a card!