Altaria

Mega Altaria is one of the bulkiest Pokemon in 1v1. With its unique Dragon / Fairy typing, it can take on Dark-types such as Mega Gyarados and Mega Sableye as well as Dragon-types such as Garchomp, Dragonite, and Mega Charizard X. Its amazing natural bulk allows it to tank both physical and special attacks while simultaneously recovering 50% of its health with Roost. After Mega Evolving, it gains Pixilate for a powerful STAB attack in Hyper Voice. Mega Altaria also has access to useful setup and coverage moves between Cotton Guard and Fire Blast, which aid it in withstanding damage from the many powerful physical attackers that occupy 1v1 such as Mega Charizard X, Landorus-T, and Mega Heracross as well as taking on certain Steel-types that resist its STAB Hyper Voice such as Genesect and Kartana. However, Poison-types such as Naganadel and Mega Venusaur, Steel-types such as Heatran, and Fairy-types such as Mega Gardevoir and Magearna threaten it. Additionally, due to its relatively low Speed, Pokemon that can outspeed it or hinder its Speed stat such as Smeargle, Jumpluff, and Vivillon take advantage of it.