>>28377349I was about to add that as well, crossgen evolutions. Unfortunately a lot of them involve trading bullshit which doesn't usually get down midgame.
If you manage to use Porygon-Z, or a Mega evolved crossgen evolution (Scizor, Steelix, and Gallade are the only options so far), you could even count it as three generations if you felt like it.
With all this crossgen bullshit, I'm tempted to try a team of Pokemon that were all introduced in Gen I, but have since been updated with Alolan Forms, Megas, and cross-gen evolutions.