It has been a while since I played one but I remember really enjoying Pokémon Unbound with some caveats. Those being, they decided to change typings for the hack. So my Charizard and Ampharous were Dragon type and it messed up my team dynamic pretty bad. Other than that no complaints at all. I think that one had QoL for HMs too where you can use any HM without teaching it so long as a Pokémon in your party can use it. However, I could be confusing it with another one, again, it has been a while.

There's also another where you are a member of team rocket, and its really cool. It follows the story of Red/Blue/Green with a twist of what team Rockets intentions truly are and, by the end, it will have you rooting for team rocket pretty hardcore. There are a few rocket hacks out there but I think this is the most popular one.

I've enjoyed Ultraviolet. I remember seeing a clip of a fan made pokemon game that had a pretty unique art style. I think they remade it unreal 5? It looked nice, but I haven't been able to locate it for awhile so perhaps it either got taken down or was fake.

Crystal Clear and all of the Drayano hacks are great if you want close to stock with every QoL mod you could ever dream of. You can optionally patch for type changes or not if memory serves

Can’t resell a physical game with a key code like literally every steam/ea/epic/whatever DD platform that almost all devs pigeonhole you into though.

IMO physical transfer rules should apply to digital.