In Yu-Gi-Oh! Master Duel, you will be purchasing numerous card packs to try and get the best cards possible to make multiple decks to take into a duel. While you could play with just the starter deck, that would get pretty boring, and you would find its shortcomings pretty fast. In some past games, upon opening card packs, players would use the system to essentially trade those cards for another chance to open a pack with potentially better cards inside. Does Yu-Gi-Oh! Master Duel allow you to reroll packs?
Overall, there is not a way to reroll packs in Yu-Gi-Oh! Master Duel. Once you purchase card packs and open them, those cards are automatically transferred to your card library. That being said, upon completing the tutorial, you are given enough free gems to purchase ten Master Packs from the in-game shop. If you wanted to, you could uninstall the game, reinstall it, go through the tutorial again, and purchase the ten packs to see if you get something better. As long as you have not linked your account, you can continuously do this. However, in the grand scheme of things, we see this as a waste of time.
Yu-Gi-Oh! Master Duel has a crafting system where you can get rid of old cards for points that can be used to generate new cards. If you are getting a lot of cards you don’t see yourself using in the future, you can dismantle them for the resources to generate something you will use. With this system in place, we don’t recommend going through the hassle of setting up and rerolling just for a few card packs that aren’t guaranteed to be anything great.