Four: Zombie Chow
Zombie Chow is a card that new players dislike and veterans love. Healing your opponent doesn’t sound great, right? Well it’s not, but having a one mana 2/3 is. If you are lucky enough to draw Zombie Chow on turn one, you immediately have all of the initiative for the entire game. Zombie Chow beats almost every other one drop and many two drops, allowing you to press your tempo advantage hard. Also, if you play it on turn one you often won’t care that your opponent has been healed, as they would not have lost much health at that point anyway.
Zombie Chow is so strong that he even does wonders in fast decks like Hunter, despite being a defensive card. The only weakness to playing Zombie Chow in any deck is the fear that you’ll draw it late game when you need something big.