There are many contenders, but the best is probably Zygarde-50% with Power Construct, credit to sumwun.
The sole ground-type legendary available in SM without migration, Zygarde serves as a bulky setup 'mon, with moves such as Coil, Dragon Dance, and Glare to help boost its offensive and defensive prowess.
Zygarde @ Leftovers
Ability: Power Construct
EVs: 12 HP / 216 Atk / 48 SpD / 232 Spe
Adamant Nature
- Dragon Dance
- Thousand Arrows
- Substitute
- Dragon Tail
Zygarde-50%'s Substitute set from Smogon enables it to reach its monstrous Complete Form quicker while setting up D-Dances, while Thousand Arrows hits most, if not all of the meta game neutrally. Dragon Tail works well with hazard stacking teams, making its moves unresisted in Ubers.
Zygarde @ Leftovers
Ability: Power Construct
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature
- Thousand Arrows
- Glare
- Rest
- Coil
Glare and Coil sets can also be run with a more defensive role, but that wouldn't let it function as a great sweeper.
Some other valuable Ground-type sweepers include Excadrill, Garchomp, Landorus, Landorus-T, Mega Swampert in Rain, etc.
Hope I helped!