
Absol @ Absolite
Justified
252 Atk / 4 SpA / 252 Spe Naive nature
- Protect
- Sucker Punch
- Play Rough
- Ice Beam
Absol requires a lot of prediction to use, but I like it a lot. I usually lead with Absol unless I think my opponent is going to try and immediately set up. It gives hazard setters a really bad day, and with protect I can transform for free and switch it in vs status inflictors or hazards as needed. Sucker Punch and Play Rough are pretty standard. Ice Beam is a really nasty surprise vs Landorus, Gliscor, and Garchomp especially.

Sylveon @ Leftovers
Pixilate
252 HP / 128 SpA / 128 SpD Calm nature
- Hyper Voice
- HP Fire
- Wish
- Heal Bell
Sylveon takes special hits like a champ, which lets it switch in very easily. Hyper Voice is powerful enough to one or two hit KO a surprising number of things, which lets me maintain momentum and can catch people by surprise if they're expecting a pure wall. Heal Bell is a real necessity to avoid having my team crippled by a status inflictor. Wish is handy to help with switches, especially when they've got hazards up. HP Fire hits the inevitable steel switch in.

Gengar @ Choice Specs
Levitate
4 HP / 252 SpA / 252 SpD Timid nature
- Shadow Ball
- Thunderbolt
- Psychic
- Sludge Wave
IMO, Gengar's greatest strength is its immunities to a whole shitload of common attacks. It pairs really nicely with Tyranitar and Absol because it can switch into the inevitable fighting type and then OHKO with Psychic. Sludge Wave is disgustingly powerful with the STAB and the specs, and can often OHKO things that are neutral to it. Shadow Ball is almost as powerful as Sludge Wave, and Thunderbolt gives good coverage. Gengar is also my main revenge killer.

Tyranitar @ Leftovers
Sand Stream
252 HP / 252 Atk / 4 Spe Adamant nature
- Stealth Rock
- Roar
- Earthquake
- Stone Edge
Tyranitar is a little bit shaky on the defensive side with all its common weaknesses, but it also has some good resists, so it can switch in fairly easily. Generally I'll use it to threaten something out and then set up rocks on the switch. Roar is a bit of a crapshot with regards to TTar being able to take a boosted hit, but I don't really have anywhere else to put it. The sandstorm is useful for breaking sashes and Multiscale.

Volcarona @ Leftovers
Flame Body
4 HP / 252 SpA / 252 Spe Timid nature
- Quiver Dance
- Fiery Dance
- Bug Buzz
- Giga Drain
IMO, Volcarona is the best special sweeper in OU. Quiver Dance is an absolutely amazing boosting move. After one boost, I can eat a Hydro Pump from Rotom-W and then Giga Drain my HP back next turn. Fiery Dance and Bug Buzz are both excellent STAB moves. Volcarona does have problems vs fire types, especially Talonflame and Heatran, and I've considered replacing Giga Drain with HP Rock to compensate, but I think I like the increased survivability better. Volcarona also makes a great switch-in vs physical attacks that it resists for the chance to burn.

Scizor @ Leftovers
Technician
252 HP / 128 Atk / 128 Def Adamant nature
- Bullet Punch
- U-turn
- Superpower
- Defog
Scizor kind of fills the gaps in my team. I needed something with a bit of physical bulk that could defog or spin and also hit back to maintain momentum, and Scizor works pretty much perfectly. U-turn lets me switch in a more fragile sweeper, and Bullet Punch is a great revenge killer. Superpower gives coverage.
I've peaked at around 1550 on Showdown with this team, so it does okay. I do have weaknesses to some pretty common mons, though, namely Swords Dance Pinsir and Belly Drum Azumarill. Heatran is obnoxious because it switches out every time TTar comes in, so I can't get rid of it and it usually stays around to wall me the whole game. Charizard also gives me trouble because I rely so heavily on prediction, and I never know which mega evo my opponent is using.