After some testing I have found these two pokemon to be particularly deadly.

Regice @ Leftovers Trait: Clear Body
EVs: 252 HP / 252 Def / 4 SDef
Bold Nature (+Def, -Atk)
- Charge Beam
- Ice Beam
- Rest
- Sleep Talk
Regice has proven to be a very competent sweeper, and an effective stallbreaker. BoltBeam coverage lets Regice hit every Pokemon neutrally, and Charge Beam has the chance to boost Regice's Special Attack letting him attempt a sweep. Rest + Sleep Talk give Regice reliable recovery as well as Status Immunity.

Scraggy (F) @ Eviolite
Trait: Shed Skin
EVs: 252 HP / 252 SDef
Careful Nature (+SDef, -SAtk)
- Bulk Up
- Rest
- Drain Punch
- Crunch
Like Molk said, Scraggy is a monster in this meta. With this set he can effectively setup and heal himself. With Eviolite he is very bulky, and when he uses Bulk Up, he is even harder to take down. Drain Punch lets Scraggy heal himself without resorting to rest, and is his preferred Fighting-Type STAB. Crunch is used for pokemon like Beheeyem, Swoobat, Natu, and Frillish.