Garchomp

Choice Band Garchomp's sky-high Attack stat combined with its strong movepool and nice Speed tier makes it a premier offensive presence in the metagame. Its Speed stat allows it to just barely outspeed base 100 Speed Pokemon like Mega Gardevoir, Mega Medicham, and Volcarona, which makes running Choice Scarf not much of a necessity. A useful Dragon / Ground typing gives it a powerful STAB Outrage and Earthquake able to take down common metagame threats like non-Choice Scarf Kyurem-B, non-defensive Mega Mawile, and Aegislash. Despite having a powerful offensive presence, there's much to be desired for with Garchomp's defensive capabilities. Almost any Pokemon holding a Choice Scarf, like Porygon-Z, Kyurem-B, Genesect, and Dragonite, can outspeed and KO it with ease. It also has a hard time against threats that naturally outspeed it like Mega Lopunny and Greninja. Garchomp also struggles with physically defensive Pokemon that it can't KO turn one, such as Metal Burst Mega Mawile, Mega Gyarados, and Mega Altaria, and they can usually KO Garchomp outright or after setting up.