Mono green devotion Tooth and Nail deck. It's been done before, I'm just putting it here so I have access to it.
Ramp as fast as possible to 9 mana, entwine Tooth and Nail during your first main phase, tutor Xenagos, God of Revels and Emrakul, the Aeons Torn, then drop them into play. Xenagods ability triggers on combat, then you can swing with a hasty 30 powered Emrakul.
You can make enough mana in this deck to hardcast Emrakul too if you draw it and don't find a Tooth and Nail.
Kessig Wolf Run can be good, because if you're playing against someone spamming tokens, if you have 2 mana left over you can give Emrakul trample. Generally, that isn't necessary, but overkill can be fun. It also provides a solid backup strategy if you never find the combo. Pumping Primeval Titan can finish games pretty quickly too.
You can also play this deck like an Eternal Command deck, playing Primal Command, tutoring Eternal Witness and either gaining life or bouncing your opponents lands to the top of their deck.
Or bounce a land, tutor Primeval Titan. Play Titan, tutor up Kessig Wolf Run and Nykthos, Shrine to Nyx with the ETB ability.
This deck can close out games very quickly with a few different draws, as long as you can find one or two ramp pieces.
