I'd like a Dratini. But if you don't have one ready or it would take awhile/you already have a different Pokemon I'd take ready instead I'd be fine with instead a Gastly, Scyther, Marill, or Axew.
I don't care about them being shiny, having EVs, or Nature. 5IVs are fine with me as long as the imperfect one is in the attack stat they won't use (or in Marill's case Special Attack) or HP.