Klefki can do hazards and screens with priority, but I'm not sure how viable it is in Gen 8 OU.
Klefki @ Light Clay
Ability: Prankster
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
IVs: 0 Atk
- Light Screen
- Reflect
- Spikes
- Foul Play
Grimmsnarl can set up dual screens, though it doesn't have access to entry hazards (but it's in UU, and viable in OU).
Grimmsnarl (M) @ Light Clay
Ability: Prankster
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Light Screen
- Reflect
- Thunder Wave
- Spirit Break
OK, onto the wall breakers.
Physical Wall Breakers
Azumarill @ Sitrus Berry
Ability: Huge Power
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Belly Drum
- Aqua Jet
- Knock Off
- Play Rough
Forever & always my favorite sweeper/wall breaker. Sitrus Berry heals Belly Drum recoil. Huge Power doubles its Attack. Adamant boosts its Attack since Aqua Jet spam is the way to go. Belly Drum maxes out its Attack, and, along with Huge Power, it hits like a truck. Aqua Jet is STAB an priority, which compliments its low Speed. Knock Off removes items. Play Rough is Fairy STAB.
Conkeldurr @ Flame Orb
Ability: Guts
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Drain Punch
- Facade
- Knock Off
- Mach Punch
A Cosmog once told me to run this set on my Conkeldurr, and it's very good. Usually, investing into Speed on a 45 base Pokemon isn't the best idea, but it works. Flame Orb activates Guts. Drain Punch is STAB that heals it. Facade deals double damage with the burn. Knock Off removes items and hits Ghost types. Mach Punch is STAB that has priority.
Scizor @ Focus Sash / Life Orb
Ability: Technician
EVs: 252 HP/Spe / 252 Atk / 4 SpD
Adamant Nature
- Swords Dance
- Bullet Punch
- Knock Off
- Bug Bite
Another good wall breaker. Focus Sash can be used for a (usually) guaranteed Swords Dance, or a Life Orb for extra power. Technician boosts Bullet Punch and Bug Bite. Swords Dance is to boost its Attack. Bullet Punch is STAB boosted by Technician, plus it has priority. Knock Off removes items. Bug Bite is STAB boosted by Technician.
Rillaboom @ Choice Band
Ability: Grassy Surge
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- High Horsepower
- Wood Hammer
- U-turn
- Drain Punch / Superpower
Finally, Rillaboom. Choice Band boosts power. Jolly is for a bit more Speed. High Horsepower is coverage. Wood Hammer is STAB boosted by Grassy Terrain. U-turn is for pivoting out of the Choice Band. Drain Punch is for healing, but Superpower can be used to do extra damage.
Special Wall Breakers
Dragapult @ Choice Specs
Ability: Infiltrator
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
- Draco Meteor
- Fire Blast
- Shadow Ball
- U-turn
Generic Pult set. Specs are for additional power. Timid is for a bit more Speed. Draco Meteor is STAB. Fire Blast hits Ferro and Scizor. Shadow Ball is Ghost STAB. U-turn is for pivoting out of the Specs.
Volcarona @ Heavy-Duty Boots
Ability: Flame Body
EVs: 252 SpA / 4 SpD / 252 Spe
Timid Nature
IVs: 0 Atk
- Quiver Dance
- Fiery Dance
- Bug Buzz
- Psychic / Giga Drain
Volcarona is insanely powerful after a few Quiver Dances, and it can take out Pokemon that resist its moves with relative ease after setting up. Heavy Duty Boots prevent Stealth Rock damage, which would normally take half of its health. Flame Body is for the burn chance, giving it fake Defense. Quiver Dance raises its Special Attack, Special Defense, and Speed, making it a lethal Special Tank/Sweeper/Wall Breaker. Fiery Dance is STAB with a chance to raise its Special Attack. Bug Buzz is STAB. Psychic can be used for Toxapex, or you can use Giga Drain for (most) Water and Rock types, +it heals it.
Magnezone @ Choice Specs
Ability: Magnet Pull
EVs: 248 HP / 8 Def / 252 SpA
IVs: 0 Atk
Modest Nature
- Thunderbolt
- Volt Switch
- Flash Cannon
- Body Press
Magnezone has huge 130 base Special Attack, making it especially dangerous. Also, it has a niche in being able to trap Steel types, which it 4x resists their Steel STAB (luring a Steel type with Clefable is probably a good strategy). Choice Specs are for even more power. Thunderbolt is STAB. Volt Switch is STAB that allows it to pivot out of its Choice Specs. Flash Cannon is STAB. Body Press uses its great Defense stat for coverage.
Hope this helps! :)