Metagross @ Weakness Policy
Nature: Jolly
Ability: Clear Body
EVs: 252 Atk / 72 Def / 184 Spe
- Agility / Zen Headbutt
- Meteor Mash / Bullet Punch
- Ice Punch
- Earthquake
Metagross is a great psuedo-legendary, boasting high defensive and offensive stats. Because of this, Weakness Policy is often used (82.500% of the time). It can tank a hit and boost it's offensive capabilities at the same time. Metagross also somewhat suffers from 4 Moveslot Syndrome. It has amazing coverage. Technically it has BoltBeam coverage with Thunder/Ice Punch, but Earthquake is quite spammable and covers Metagross's common Fire weakness.
Now, let's take a look at the other most used Pokemon in the tier.
-Tapu Fini: 44.66%
-Landorus-Therian: 36.64%
-Incineroar: 29.53%
-Regieleki: 26.09%
Tapu Fini can't touch Metagross, except for Scald.
Landorus-Therian's Intimidate is blocked by Clear Body, pretty much ruining the whole purpose of it as an Intimidate Pivot. Landorus can still threaten it with Earthquake. Ice Punch has a good chance to OHKO, though.
Same with Incineroar, except Metagross can usually outspeed and KO with Earthquake.
Regieleki is a bit tougher. There's no way Metagross can outspeed, and Thunder Cage has a 86.3% to OHKO. However, if Metagross can survive, it can OHKO.
252+ SpA Choice Specs Transistor Regieleki Thunder Cage vs. 0 HP / 0 SpD Metagross: 294-346 (97.6 - 114.9%) -- 81.3% chance to OHKO
252+ Atk Metagross Earthquake vs. 0 HP / 0 Def Regieleki: 428-504 (142.1 - 167.4%) -- guaranteed OHKO
Besides those, Metagross can threaten common Ice, Fairy, Dragon, Poison, Fighting, Flying, and Rock types. (Examples include the Tapus, Glastrier, Stakataka, and Rillaboom, as well as the aforementioned Regieleki, Landorus-Therian and Incineroar.)
Metagross is also a great Dynamaxer, with access to Max Steelspike/Quake to boost defenses, Max Mindstorm/Lightning for terrain, and Max Knuckle for Attack.
Sources:
Damage Calculator
Pikalytics 2021 VGC
Metagross 2021 VGC
Metagross Pokedex
