I've managed to pull myself away from Smash Ultimate and Artifact long enough to create this thread.   In E17, I did a personal challenge to see if the game could be cleared with just using 6 pokemon ever on Set mode with no items and having none of those pokemon be from Mix events (things like mystery egg where it can be one of multiple pokemon, but which one is determined at the start of the game)--pokemon of those species obtained outside of the mix event were fair game. All things