Digimon is another franchise that kids fell in love with during the early aughts, albeit, not to the same extent as Pokemon or Yu-Gi-Oh! Nonetheless, it still has a massive fan base that would love to see these critters in the real world.
Digimon is similar to Pokemon and Yu-Gi-Oh! due to its similar creature battles. However, since Digimon relies more on the stats and training than the player interactions, it should still have a unique feel all its own.
It could be similar to Pokemon Go, where you go out finding Digimon in the real world and catching them or interacting with them. It would also fit in narratively since the Digimon are digital monsters that can potentially interact with or visit our world. It could also be similar to Yu-Gi-Oh!, where you start off with Digimon and you earn more by buying Digimon online or battling other people.