This can make grabbing the last few cards of a set a challenge. You can receive copies of a card even after your playset of 3 is complete, giving you about a 1 in 117 chance to get any single card you are looking for, not accounting for rarity.
It's tedious, but 60 or so forfeits would provide every card an NPC has and between 24,000 and 36,000 duel points. Doing so rewards you with 600 to 900 duel points and a card from the opponent's pool. You can select/click your deck during your turn to forfeit. Yu-Gi-Oh! Legacy of the Duelist: Link Evolution Cheats For Nintendo Switch
