8001AEE4 0000 Tired of replaying the story? This unlocks every opponent in the "Free Duel" menu from the start.
800189F0 000F
Note: The "All Cards" code is notoriously version-sensitive. If the above doesn't work, search for a "Complete Trunk" code specific to your ROM region (USA/Japan/Europe). If you don't want every card, you can force specific monsters into your hand using memory editing. These codes require you to be in a duel and modify a specific slot in your hand. yu-gi-oh forbidden memories cheat codes