This card was banned from the Expanded format in August 17, 2018 due to its combination with Trevenant stifling creativity, preventing several strategies from being viable, and having the potential to make a major negative impact on an opponent before their first turn. It has been then unbanned starting March 5, 2021 as since the Sword & Shield expansion release the player who goes first can no longer play a Supporter card on their first turn.
While this card says, " You can use this card during your first turn...", the rule change from Sword & Shield supersedes it. Wally cannot be played on a player's first turn if that player is going first in the game. This is likely because that sentence is only meant to bypass evolution restrictions.
Wally is a rival character in Pokémon Omega Ruby and Alpha Sapphire. The Generations print's artwork depicts Ralts, a Pokémon which Wally caught and raised in all of his appearances in the core series Pokémon games. Wally is an updated version of Wally's Training.