What four Pokemon are on the Pokemon Gen 1 Mount Rushmore?

Board 8

Pikachu
Eevee
Mewtwo
Jigglypuff

Fifth is Charizard, then the rest of the starters and Gengar.

My sister, who hardly knows anything about Pokemon, namedropped Jigglypuff out of nowhere the other day and I was surprised! Jiggs has some staying power.
It's not so impossible!