(All information from Bulbapedia)

Turtwig

  • Turtwig is the heaviest of the basic forms of all of the starter Pokèmon.
  • Turtwig is the only starter Pokèmon to know a stat-raising move when initially received as a player's first Pokèmon.

Chimchar

  • Chimchar is the only starter Pokèmon that is a member of the human-like Egg Group.

Piplup

  • Piplup is the only Water-type starter Pokèmon to be based on a bird.
  • Piplup is the most selected Sinnoh starter Pokèmon in the anime. It has been the starter Pokèmon of Dawn, Kenny and Tyler.
  • Piplup was designed by Yusuke Omura.