I recced this to Steven but, repeating myself down here: would you be interested in an AU Pokémon game? bravenewworld meets your requirements - plus Connie could both raise monster friends and, if you wanted, gain Pokémon abilities herself. The setting is huge so there's lots of freedom to play around in the world and just have fun with Pokémon, but there's also an overarching plot (angry Legendaries, culture clashes between cities, etc.) if you wanted to get involved in that!