Wobbuffet's best moveset in Pokémon GO is Counter and Mirror Coat, with 4.38 damage per second, and it can deal 146.2 damage before Wobbuffet faints. This is true when battling in neutral weather.
All Wobbuffet movesets ranked
Here is a complete list of Wobbuffet movesets in Pokémon GO, ranked by their DPS and TDO. You can change the weather and the opposing Pokémon.