The very first Pokémon! ...Besides Rhydon and Arceus.
Available in all Kanto-based games, and arguably one of the best Grass starters around for its environment. It can also be obtained from Professor Sycamore in Kalos games. In Ultra Sun and Ultra Moon, Bulbasaur can also be caught on Route 2 using Island Scan on Fridays.
Completed analyses of the Bulbasaur line so far: