The clever innovation I've done is that the game started with an empty database. The game map is procedurally generated based on the map of the real world. In-game locations are real shops and parks around you in your town/city. The further you go into nature, away from towns & cities, the higher level the animals are when you encounter them.
Animal assets in-game are generated on the fly the first time a user encounters that species. That includes the full growth chain, caterpillar > chrysalis > butterfly, plus dimorphic sexes, male & female lions look different, and morphs, e.g. worker/soldier/queen ants. You can also even catch your pet and it identifies the breed, so you can play with your real pet in-game.
The game is free to play, available on iOS & Android. Let me know what cool species you catch and happy adventuring!