What's a Pokemon you have never used, and why? And the reason can't be "it sucks."

I've never used a Clefairy because in addition to typically being really rare, I've always preferred Jigglypuff as my Moon Stone needing pink blob, maybe because of Smash Bros.

I've also never used Seel or Dewgong because by the time you can catch them in any game, you probably already have a dedicated Water type that doesn't need replacing. That's the problem with a lot of unlucky Pokemon, they're always stuck at the end of the game when your "team" is basically solidified. It's mostly Ice and Fire types that get shafted like this, I've noticed.