Psychic.

Mewtwo, Mew, Guardevoir, Espeon.

Psychic is simply the type I think of when I think about cool Pokémon.

I don't know why Grass is not common as attack type. Drought teams are common and Drought teams have Plant Pokémon. Chlorophyll Venusaur with Solar Beam or Giga Drain or Ninetales, the Fire type Drought Pokémon with Solar Beam are Over Used. Like Rain teams.