(All information from Bulbapedia)

Chikorita

  • The Chikorita family is the only known evolution family of a starter Pokèmon to not have their names changed for the English release.
  • In the anime, Chikorita has the most trainers of the Johto starter Pokèmon. It has been trained by Ash, Casey, Vincent, Silver and Lyra. However, Ash is the only one who is confirmed as not receiving Chikorita as a starter Pokèmon.
  • Chikorita is the tallest unevolved starter Pokèmon at 2ft 11". (Due to this, it is the only starter Pokèmon from Generation I - III that cannot be used in the Pokèmon Jump mini game.
  • In both early artwork and the in-game sprites of Pokèmon Gold & Silver, Chikorita's body is yellow. This was later changed to light green in later artwork and Pokèmon Crystal sprites.
  • The green Pokèmon mini was modelled after Chikorita.
  • A prototype of Chikorita called Happa resembles a Chikorita without legs.

Cyndaquil

  • Cyndaquil is the only Fire-type starter Pokèmon that retains a pure Fire-type throughout its entire evolutionary line.
  • Cyndaquil is the first starter Pokèmon based on a mammal.

Totodile

  • Totodile is the tallest and heaviest unevolved Water-type starter Pokèmon.