Gourgeist Stage 1 Aggro

Gourgeist ex is the successor to Hisuian Zoroark VSTAR: a Pokémon that deals damage based on the number of damaged Pokémon you have on board. Thanks to Sky Field and various ways to get damage on your board, it can deal enough damage to OHKO anything in the format, all for one single Basic Energy. Its Psychic typing is also strong, letting it benefit from the excellent support available to the type, such as Fog Crystal, Mysterious Treasure and Lillie's Clefairy ex.

That said, Gourgeist has a fatal flaw: it doesn't actually do much. Yes, it can OHKO stuff, but so do other aggro decks, which also tend to have more to offer, whether it's spread attacks, extra Prize taking, or some form of disruption. Gourgeist has the very mild Ghostly Touch second attack, which is simply not strong enough in the current metagame.