I just realized on showdown and in game that people use Rotom-Wash alot, why is that?
The main reason is its great typing. Being Water/Electric it has 5 resistances, 1 immunity and only one weakness with Levitate, and Grass isn't really a common type in OU either. It is also a natural counter to Talonflame and other Pokémon, making it an ideal Pokémon in the current OU meta game. Its Hydro Pump is nothing to laugh at either, checking Heatran, Gliscor and such.