>>41526843>>41526859Yeah, mainly the gen 3 games because it has the combination of being understood enough to do this kinda thing + having the room for all these mons, though there's a couple of GB hacks that straight up replace old mons with the newer ones.
None exist for Gen 8 yet because it's so new but give it a matter of time. In the mean time, look up Nameless Fire Red Project and Kalos Crystal. Theta Emerald Renev might be worth looking at too if you're bold enough to risk the glitches.