Altaria

Mega Altaria's fantastic typing, high all-around base stats, and deep movepool filled with useful offensive, defensive, and supportive options combine to make it one of the best Pokemon in the tier. Its powerful Pixilate-boosted Return makes it one of the tier's most dangerous sweepers with Dragon Dance, and its Dragon / Fairy typing allows it to act as a solid check to Pokemon like Latias, Hydreigon, and Crawdaunt. Access to other options like Fire Blast can make it easy for Mega Altaria to lure and weaken or KO Pokemon like Scizor and Mega Aggron, while Earthquake can break through Pokemon like Nidoqueen and Tentacruel, allowing Mega Altaria to choose its counters and making it harder to switch into. In addition, options like Facade and Refresh let it act as one of the best stallbreakers in the tier. It can also take advantage of its great bulk and access to Roost to act as one of the most sturdy defensive Pokemon in the tier, capable of taking hits from Pokemon like Krookodile and Infernape while KOing them in return thanks to its natural power. It can also run a defensive Dragon Dance set on stall teams, acting as a potent late-game sweeper while still retaining good utility through Heal Bell and its great bulk and typing. Mega Altaria is, however, held back by its low Speed, which makes it slower than Pokemon like Nidoking, Gengar, and Lucario before a boost, and particularly fast Pokemon like Mega Manectric and Mega Aerodactyl can still outspeed a +1 Mega Altaria. It also can't fit all the moves it wants onto one set, making it a little more scary on paper than it is in practice. It's often forced to Mega Evolve early in order to check Pokemon like Crawdaunt and Hydreigon, which can be difficult to do and also forces it to give up Natural Cure and its Ground immunity. Finally, the prevalence of Pokemon like Amoonguss and Quagsire can make it difficult for Mega Altaria to sweep, and even if it breaks past its defensive answers, it's easily revenge killed by priority users like Mimikyu, Mamoswine, and Scizor.