I do have some questions to add to this-ANYGEN GOES
1. How would moves on Pokemon in older generations interact with effects that weren’t introduced yet? For example, would RBY Zapdos have a chance to miss its Thunder in Rain? Would RBY Mewtwo’s Psychic be boosted by Psychic Terrain?
2. Would we let Smeargle Sketch the special starter moves from Let’s Go, such as Sparkly Swirl or Baddy Bad?
3. What about changes to the type chart? Would RBY Mewtwo be immune to Ghost? Would a GSC Steelix resist Dark?
4. Damage formulas have changed throughout Pokemon’s history. Would this be implemented in some way, with older-gen Pokemon using older damage formulas?
5. Would this format support Pokemon from LGPE, BDSP, Legends: Arceus, and Legends: Z-A? Z-A in particular is rather interesting, since it gives us Zygarde-Mega in addition to the OHKO moves becoming base 250 power.
6. If supported, how would Let’s Go and Z-A mega evolution mechanics work? Would you simply let, say, a Charizard from LGPE to mega evolve into either of its mega evolutions without a stone? Would a Charizard-Mega-Y from LGPE or Z-A have Drought, or no ability?
This format is really interesting as a premise, but would probably be a nightmare to code.
Anyways, on a final note, here’s a team I threw together (assuming Z-A is allowed)-
EDIT: Most of my questions were asked based on the assumption that the list of allowed Pokemon is based on the Pokedex of the selected generation they are to be from, and not National Dex or SV Dex. For example, I am assuming that USUM Kartana would be allowed, but not SV Kartana.

