Because the game is dead, mods are no longer actively updated on mainstream app stores. You might still find them on:
If you have a rooted Android device, you can edit the local save file: yugioh duel generation mod unlock all cards
For players looking for a more modern experience with active online play and a massive card pool, Konami has replaced this title with and Yu-Gi-Oh! Duel Links . Because the game is dead, mods are no