There are only two Pokemon that resist Grass, Water, Ice and Dark, and that is Sap Sipper Marill/Azumarill. Due to their unique typing and Ability they are the only ones who resist all 4 types.
For the sake of it I will include more viable Pokemon that resist 3 of the types:
Resist Grass, Ice and Dark:
Resist Water, Ice and Dark:
Resist Grass, Water and Dark:
Resist Grass, Water and Ice:
Source: http://pokemondb.net/tools/type-coverage (as this source dont account for abilities Sap Sipper Marill/Azumarill dont show up there, but they still resist all 4 types).