Good question. GX cards were introduced in the Pokémon Sun & Moon set, and they’ve been a part of each series ever since. A Pokémon card with the GX title has far more HP and stronger attacks than their normal versions, and they feature stunning artwork, too. For instance, the ultra-rare Palkia-GX card available in the Forbidden Light series has access to the devastating “Zero Vanish GX” attack. If Palkia-GX uses it, the opponent is forced to shuffle every single Energy card attached to their Pokémon back into their deck. Just be thankful that these game-changing GX attacks can only be used once per player, per game.