Oh it would probably be Yokai Watch. Its like one of my favorite things ever. I could go on about how I think YW3 is such an amazing game and I'm shocked that they managed to put that much content into a game.
Like, triple the map of the first game, tons of side content, and literally like an entire functional version of YW blasters as like an entire separate mode? It's insane. Plus I think the designs are super cute and the aesthetic is super calm and pretty. I even like the anime despite its abundance of toilet humor.