Wait, I need to do some out loud counting.
We had the Classical Era, the Neo Era, the E-Card Era, the EX era (yes, I know the early phase of that era was another variant of the E-card era, but we know from the jumbo starters collection what TPCI does to e-reader EX era cards), the DPPt era, the HGSS era, the BW and XY eras (which are arguably the same aesthetically, but to begin with we will keep them separate), XY Evolutions, and the Sun and Moon era. That makes 10.
In the Base Set era, we had Dark Pokémon and Trainers Pokémon. Twelve.
In Neo we had Light Pokémon and Shining Pokémon. Fourteen.
In E-Card we had Crystal Pokémon. Fifteen.
In EX we had ex Pokémon, Star Pokémon, Team Magma's and Team Aqua's Pokémon, redesigned Dark Pokémon, Rocket's Pokémon (again rebalanced, since Rocket's Pokémon appeared as Trainers Pokémon in the Classical Era), and two different versions of Delta Species Pokémon, monotype and dual type (Metal). That makes twenty three (I'm not even half way through my estimate and I've already eaten through almost all 25 slots! Who knew this era had so many gimmicks?)
In DPPt we had Pokémon Lv. X and Pokémon SP. Twenty five.
In HGSS we had Pokémon Prime and Pokémon LEGEND. Twenty eight, since Pokémon LEGEND come in two halves.
In BW we had Pokémon EX and Team Plasma Pokémon. Thirty.
In XY we had Mega EX Pokémon, Break Pokémon, and Ancient Trait Pokémon. Thirty three.
In Sun and Moon we had GX Pokémon, Prism Star Pokémon, and Tag Team GX Pokémon. Thirty six.
Then we have Venusaur, Charizard, Blastoise, and Pikachu. We all know these cards will be included in the set. That makes... FOURTY.
What cards do you think we can remove for sure? And do you think we should also consider cards like Team Flare Gear or ACE Specs?