Tank hits with leavanny and kricketune so that you can unleash Dustox and take multiple prizes (read everything on the card). If your opponent has lots of ultra beast, you can play sceptile, but otherwise just keep univolved to keep getting grass pokemon you need. You can use decidueye to setup damaged pokemon for Dustox. Vileplume for if your oppenent plays lots of basic, the kinda just auto lose.
Every card here I own IRL so if you are wondering why I don't have a caterpie with the ability: adaptive evolution, or a torterra, that means I don't own the card. Trust me, I've searched my collection dozens of times for those cards.
BTW It didn't let me post this as a GLC deck because apparently I am not following the rules, which is a lie, i only have 1 of every card. It said: "Gym Leader Challenge is a Singleton Format and cannot contain more than 1 card with the same literal name (excluding Basic Energies)."