GameStop offers one credit card called the GameStop PowerUp Rewards Credit Card. It offers no rewards points and high, soul-crushing interest rates. Basically, it's nothing worth mentioning.
A Pro Membership is all you will need to get the most out of GameStop.
If you want to maximize your return on your GameStop purchases, I recommend picking up a card that earns general everyday rewards. You can use our Best Credit Card Rewards Tool to find the best card for you based on the spend amounts you enter (including GameStop purchases).