http://hearthstone.metabomb.net/game-guides/dealing-with-area-of-effect-removal
It's a bit outdated, but it's still a baseline. I would add...
Ravaging Ghoul (warrior, 3, deals 1 to all other minions)
Brawl (warrior, 5, destroy all but 1 minion)
Dragonfire Potion (priest, 6, 5 damage to all...