Four: Fireball
In arena, direct damage can be very difficult to find. I’m sure everyone has been in the situation where your opponent has five health and you just can’t find that last little bit to finish him? Well Fireball is the answer. Fireball is premium removal, killing almost every minion for only four mana. Cards like Pit Fighter, which are very common in arena, directly lose to Fireball, a cheaper removal. And if you are ahead, throwing Fireballs at your opponent is always a pleasant way to end the game!
Fireball is also a common card, so having two is fairly likely. This means that you can easily finish off an opponent from twelve life. The utility of Fireball is matched by very few cards, giving it a solid spot on our list.
