Archeops

With its gargantuan mixed attacking stats and a blazing Speed that lets it outspeed almost all of the unboosted metagame, Archeops has established itself as one of the best Pokemon in the tier. Its offensive stats are matched with an equally strong offensive movepool, with a wide variety of both special and physical moves that allow Archeops to potentially beat almost every one of its counters. In particular, STAB Acrobatics is one of the most spammable and powerful attacks in the tier, though it comes at the price of not being able to viably run an item. Archeops's typing is even decent defensively, giving it resistances to Normal-, Fire-, Bug-, and Flying-type moves, and its access to reliable recovery in Roost and support moves in Taunt and Defog gives Archeops both defensive and supportive utility. While these would all be traits of an easily OverUsed or even Ubers Pokemon, Archeops's wings are clipped by Defeatist, which makes Archeops virtually useless when it's below half HP. A Stealth Rock weakness and low defenses don't do Archeops any favors in compensating for its ability, either. In addition, very common Pokemon such as Rhydon, Steelix, and Regirock check Archeops with ease if it lacks the appropriate coverage move.