Gardevoir

Mega Gardevoir is an admirable offensive nuke in the 1v1 metagame, able to set up on and one-shot several bulky Pokemon such as Mega Gyarados, Tapu Lele, and Zygarde-C with a Pixilate-boosted Hyper Beam. In addition, Mega Gardevoir also has access to tools such as Hyper Voice to provide coverage against Substitute users, as well as access to utility options in the form of Will-O-Wisp and Calm Mind, which can be very useful in breaking through physically offensive threats such as Dragonite, Donphan, and Golem and bulkier special attackers such as Tapu Lele, Primarina, and Tapu Fini. Before Mega Evolving, the ability Trace allows Gardevoir to acquire the ability of its foe, which is indispensable against certain Pokemon such as Dragonite and Mega Gyarados. Unfortunately, its naturally poor defenses leaves Mega Gardevoir quite vulnerable to faster physical attackers that populate the metagame, such as Mega Lopunny, Garchomp, Mega Pinsir, and Choice Scarf Haxorus. It also has a terrible matchup against most of the Steel-types in the metagame, which all resist both Mega Gardevoir's Fairy- and Psychic-type STAB moves, such as Mega Metagross, Magearna, and Mega Mawile.