Pokémon is described as 'Players assume the role of trainers, catching and battling monsters to become the best, with games spanning various consoles since 1996' and is a role-playing game in the games category. There are more than 25 games similar to Pokémon for a variety of platforms, including Windows, Android, iPhone, iPad and Android Tablet apps. The best Pokémon alternative is Palworld. It's not free, so if you're looking for a free alternative, you could try PokeMMO or Pokémon Island. Other Pokémon like games are Megami Tensei, Tuxemon, Pokémon Survival Island and OpMon.
I like all of the monsters, and the story!