Mech Warper + Metaltooth Leaper is definitely the best combo.
Game ends by turn 3 (coin) or 4. When you have 3 Mech Warpers, you play when you have 3 Mana available and unload everything.
Otherwise, for a neutral setup, Murloc Tidecaller and Grimscale Oracle work.
If you hate aggro, then a Priest with Doomsayer + Resurrect sometimes works. The other is Paladin with Humility + Forbidden Healing.
Mill Druid with Innverate/Naturalize + Coldlight Oracle is a counter for slow decks.
If you hate decks that rely on spells, then a Druid with Innervate + Loatheb works.