I'd like to mention a mon that while not meta defining, is something I've been using a lot and think is underrated.
Gallade (M) @ Life Orb
Ability: Justified
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Close Combat
- Zen Headbutt
- Shadow Sneak/Knock Off/Poison Jab
At face value Gallade seems a tad too slow to be a great mon, but it actually has a lot of value, emulating Mega Medicham's typing of Psychic/Fighting which gives fantastic coverage, allowing it to hit everything but psychic's neutrally across it's STAB. It also has a really nice ability to take down Ferro/Pex cores, with a guaranteed 2HKO on Pex and a roll to OHKO Ferro after rocks or any chip, both of those with full physical investment. It's last moveslot is more variable and gives it the option to draw from it's wide movepool to take on a lot of threats. Shadow Sneak is awesome against HO which is essential given it's so common because it gives you a safety net to pick off a weakened threat, which has personally saved my team more than once from sweepers, but in the long run Knock Off looks like it'll be the stronger move, giving Gallade the ability to take down defensive Mew on the predicted switch and having awesome utility of removing items, which not so many mons have now, it also gives it an awesome match-up with Corsola since it can remove eviolite. I slashed Poison Jab on there for it's ability to take down Clef, though it doesn't do a whole lot else for Gallade. The other great thing about this is it's huge number of utility moves, allowing it to run Thunder Wave, Will-o-Wisp or Toxic to cripple checks coming in or Scarf + Trick to allow it to take on Hyper Offense as well as giving it extra utility against stall, if you're feeling really gutsy you can even run screens + memento or Trick Room to enable other sweepers. However, one of the biggest benefits of Gallade is it's ability to use swords dance to give it OHKOs against a huge portion of the meta, making it so that even Corviknight has to be careful. Gallade also has some more than decent natural special bulk, meaning it can take a hit in a pinch, though most special attackers are psychic/ghost/fairy at the moment so it's not as valuable as it seems. This all makes Gallade very strong against stall and balance (even though balance isn't at all common because dynamaxing is broken) and gives it enough ability to not be dead weight against hyper offense, making it a useful member in some teams. I also haven't really mentioned dynamax potential, but Gallade can really do some damage once it dynamaxes, making it capable of breaking past most it's checks, especially after a swords dance or max knuckle.
That said, this thing does have some trouble with Hippowdon & Mimikyu, it also definitely isn't the most valuable pokemon against hyper offense, needing chip on dragapult to revenge it or an SD up to potentially kill it outright and while technically capable of defeating some Hydreigon & Excadrill, it'll take heavy damage and LO recoil doing so, plus not doing too much to Gyarados & flat out dying to Hawlucha (but what can take them at the moment?). Also this will definitely be overshadowed by Cinderace once it's HA is released. But for now, it's got a niche in psychic/fighting STAB with a wide and useful movepool including Knock Off and priority.
A couple calcs:
252 Atk Life Orb Gallade Zen Headbutt vs. 252 HP / 252+ Def Toxapex: 174-211 (57.2 - 69.4%) -- guaranteed 2HKO after Black Sludge recovery
252 Atk Life Orb Gallade Close Combat vs. 252 HP / 252+ Def Corviknight: 173-204 (43.2 - 51%) -- 98.8% chance to 2HKO after Stealth Rock
252 Atk Life Orb Gallade Close Combat vs. 252 HP / 252+ Def Ferrothorn: 296-351 (84 - 99.7%) -- 37.5% chance to OHKO after Stealth Rock and Leftovers recovery
252 Atk Life Orb Gallade Knock Off (97.5 BP) vs. 240 HP / 52 Def Mew: 255-302 (63.5 - 75.3%) -- guaranteed 2HKO after Stealth Rock
252 Atk Life Orb Gallade Poison Jab vs. 252 HP / 252+ Def Clefable: 195-231 (49.4 - 58.6%) -- 69.1% chance to 2HKO after Leftovers recovery
252 Atk Life Orb Gallade Close Combat vs. 252 HP / 252+ Def Rotom-Wash: 172-203 (56.5 - 66.7%) -- guaranteed 2HKO after Leftovers recovery
+2 252 Atk Life Orb Gallade Shadow Sneak vs. 0 HP / 4 Def Dragapult: 278-330 (87.6 - 104.1%) -- 25% chance to OHKO