Cyndaquil, Typhlosion can be taught ThunderPunch >;] or Empoleon, I like offensive types >.> particularly in special atk and those two have it in spades, not to mention Empoleon and Typholosion can quickly get rid of Gyrados via ThunderPunch or Grassknot provided that Gyrados isn't on a diet >.>
Imo Treecko is the only viable grass starter, he brings great offense to a type that's offense is good but is weakened by the fact that they're easily dispatched by common flying type pokemon which often have high attack rendering Chikorita quite bad off, especially in it's own game where the first gym leader is Faulkner e-o