Theorycraft on Silence priest :)

Mulligan:

Try to find some cheap minions, like [Hearthstone Card (Nortshire Cleric) Not Found], Ancient Watcher, Madame Lazul or Dalaran Librarian. Power Word: Shield is ok, too.

Your win condition are silenced minions which can attack (it's quite easy to do some damage in early turns with cheap silence cards) OR an old Divine Spirit and Inner Fire combo.