Hearthpwn

This one card is better than the entirety of Attack Druid and still won't see play.

Probably would've said it was dust if Wall Priest hadn't been so successful with similarly statted minions. With Muerte and enough fat healthy boiz I can actually see this making the cut. 

Spirit of the Rhino. Also insane when buffed with Akali, the Rhino.

You could buff this with the warrior weapon too, giving it more attack and health.

This card is one badassa mofo in priest decks for epic OTKs. You play it, double two times it's health, swing health equal with attack (48/48) and kill everything-everyone. When you hit with 48 attack that board shaking is epic in itself and when you attack like 8 times in a row, the whole tavern gets orgasmic heart-attacks.

Many players underestimate it until it's too late. They sure do not make that mistake many times.