Preferably one that’s not a rom hack, though I dig those too. I’m looking for something a bit harder than the originals and maybe a bit more mature, but still fair and whimsical. I’d like a game with pokemon from as many gens as possible, and fakemons are fine too.
Pokemon Theta Emerald Renev is one of my favourites. It’s basically Emerald, but with updated mechanics, attacks, and Pokemon, so you can have up to Gen 7 Pokemon in your team. The Pokemon list also means you can complete the Pokedex mostly on your own, and other cool features. Definitely recommend checking it out.