Bulbasaur
Pokemon Red[]
Bulbasaur wasn't a major character in Red, but viewers used the Pokedex to spam Bulbasaur's cry throughout the entire game for long periods of time. This is because bulbasaur was the first in the Pokedex.
Black[]
in Black, Bulbasaurs real intentions were discovered. He was the first prophet of Root, trying to help Red on his quest.