Gardevoir

Psychic

Gardevoir's Fairy typing makes it a valuable Pokemon on Psychic teams, as it can check most threatening Dark- and Dragon-types like Mega Sableye, Kyurem-B, and Hydreigon. Gardevoirite allows it to Mega Evolve and serve as a tremendous wallbreaker. Mega Gardevoir's ability in Pixilate makes its STAB Hyper Voice devastate many threats such as Mega Sableye, Mandibuzz, and Dragonite. On the other hand, regular Gardevoir's Trace allows it to perform well against weather and Terrain sweepers such as with Swift Swim Kingdra and Sand Rush Excadrill by making it outpace and either KO them or force them out. It also has access to utility moves such as Encore and Taunt to help with status users and entry hazard setters such as Chansey and Heatran. However, Mega Gardevoir faces competition for the Mega Evolution slot on Psychic due to the type's many options in Alakazam, Latias, Gallade, and Slowbro. Gardevoir and its Mega forme also sit at an average Speed tier, making them susceptible to fast revenge killers, especially Choice Scarf users like Victini, Heracross, and Excadrill. Furthermore, Gardevoir's terrible physical bulk makes it weak to many common priority users and physical attackers such as Bisharp, Mega Scizor, and Mega Sharpedo.

Fairy

Mega Gardevoir is a great wallbreaker with Pixilate-boosted Hyper Voice and a high Special Attack stat, easily breaking walls like Clefable and Mega Slowbro. Its Psychic typing gives it good coverage and helps it check some Poison-types like Mega Venusaur, which is especially helpful for Fairy teams. It has a good movepool as well; Focus Blast gives it great coverage, and its utility options in Will-O-Wisp, Taunt, and Encore allow it to cripple physical attackers and deal with some defensive threats, respectively. Trace is a good pre-Mega ability to have, as Gardevoir can copy useful abilities to revenge kill weather sweepers, especially Sand Rush Excadrill. Mega Gardevoir also has a decent but crowded Speed tier that allows it to outspeed Pokemon like Kyurem-B and Landorus-T and Speed tie with Pokemon such as Manaphy. However, Gardevoir's low physical bulk makes it susceptible to being revenge killed by fast physical threats, and it may take lots of damage if it can't manage to KO the foe. This also makes it susceptible to priority users, especially Mega Scizor, which already has a positive matchup against Fairy. It's also easily walled by notable special walls like Chansey even with its great wallbreaking capabilities. Lastly, Gardevoir faces direct competition for the Mega slot from Mega Diancie, which has the ability to go mixed and break special walls, a higher Speed tier, and a Rock typing that helps it check Flying, Fire, and Poison teams; despite Mega Gardevoir's Psychic typing, Mega Diancie is actually a better check to Poison teams due to its neutrality to the type and ability to break past Alolan Muk.