Lucario
Maylene in the anime, like in the games, has a Lucario and it was seen in four episodes. It was first seen battling with Maylene in their training. Lucario used Aura Sphere to stop the battle of Electabuzz, Piplup, and Pikachu, and is seen battling Paul's Pokémon in a flashback. Lucario was seen again where it battled in Dawn's gym battle with Maylene, where it defeated Dawn's Ambipom and Piplup. Then, in the next episode, it battled in Ash's gym battle against Maylene. It defeated Ash's Staravia and Chimchar, but was knocked out along with Ash's Buizel, which ended in a tie. Finaly, Lucario was seen when it helped Ash and the others defeat Saturn and Team Galactic.