Cyndaquil.
I've probably said this at least twice in other topics, but it's basically a Charmander double with a slightly different moveset, different egg breeding group, and a different first evolution level. Its evolved forms are pretty much Charmeleon and Charizard doubles, too (the exception being that Typhlosion is pure Fire-type, while Charizard is Fire-Flying). I say this mostly because their base stats are the exact same as those of their Kanto counterpart's.
Also, Cyndaquil's moveset, up until the fourth generation, was pretty pathetic. It couldn't learn anything to defend itself its Ground-type weakness, not even in its final form. And as if that wasn't bad enough, it only learned 6 level-up moves (I'm not counting Tackle and Leer). I'm glad they gave it a few more level-up moves in the fourth generation.