Curse/Sleep Talk/Rest/Return Snorlax is cool but you need even more support beforehand to kill ALL Normal resists on the opponent's team. Nonetheless, I will add it.
I mentioned Salamence, but I don't really think Tyranitar and Gyarados are much better as last Pokémon - generally you don't counter them by phazing (they have Taunt anyway), but by using resistances (Claydol, Flygon, Donphan for Tyranitar and Zapdos, Aerodactyl, and again Donphan for Gyarados).