Lucario

Lucario doesn't get to lean on original-generation nostalgia, and that's part of what makes its case interesting. The sharp design and fighter energy gave later generations a Pokémon capable of standing on a card with much older heavyweights without looking out of place. Against Gengar, you're basically voting on two completely different definitions of cool. Against Greninja, swagger becomes the whole matchup. Then comes the real test: Charizard, Pikachu, or Mewtwo, where Lucario has to overcome years of childhood attachment. If you're picking the Pokémon you'd trust when the battle gets serious, Lucario suddenly becomes very hard to click against.