Gardevoir is a Psychic and Fairy-type Pokémon, which makes it weak against Poison, Ghost, and Steel-type moves. Gardevoir is resistant to Dragon and Fighting-type moves, but it takes up to 160% damage from Poison, Ghost, and Steel-type moves. Some recommended counters to use against Gardevoir include Chandelure, Metagross, Nihilego, Gengar, Dialga, Giratina, Mega Gengar, Mega Beedrill, Mega Steelix, Genesect, and Origin Form Giratina. It is important to note that Gardevoir can also learn moves that could be super effective against its counters, so it is best to plan ahead and make sure you have a strong Pokémon from one of these categories for an awaiting Gardevoir.