Weepinbell

Razor Leaf* + Sludge Bomb and Seed Bomb

The legacy Razor Leaf is recommended for its very high STAB damage output, which is the primary reason for considering Weepingbell. 

Sludge Bomb is recommended for its coverage, though its energy cost might be difficult with the poor energy generation in this moveset. Seed Bomb acts as a low energy cost charge move, which is alright for applying extra shield pressure, though also somewhat redundant with Razor Leaf's coverage. 

Bullet Seed + Power Whip or Seed Bomb and Sludge Bomb

This is a moveset if the legacy option is not available, though it is not recommended to choose Weepingbell in that scenario due to superior Grass picks. Bullet Seed offers superior energy generation which is recommended to access Weepingbell's strong charge moves. 

Power Whip is a strong STAB charge move, though it requires a modest amount of energy. Seed Bomb can be elected for a more accessible alternative, though it doesn't hit as hard. Sludge Bomb is the only option available for additional typing coverage, and benefits from STAB to deal decent damage.