>>719680189
Super Mariomon (GBA)
Star Beasts (GB)
Vega (GBA), Altair (GBA), and Sirius (GBA) are all by the same guy.
If you want Digimon then there's Digimon Crystal (GBC), Emerald Project (GBA), and Nova Red (GBA). Emerald Project is the best one of the three if I remember right.
Pokemon Sage (There's a demo but good luck whenever that gets released).

Then there's the pseudo-fakemon that you can find in Pokemon Uranium and Infinite Fusion if you count those.

I cannot stress enough how good Super Mariomon was. Just enable level scaling and level caps and it's the perfect difficulty outside of the legendaries, postgame teams, and dev teams. Everything about the game feels like a polished release Nintendo themselves would authorize.