The greatest champs outside of lane to counter Blitzcrank include Caitlyn, Zeri, and Jinx. These champs are all good at countering Blitzcrank with win rates over 55%. Even if these Blitzcrank counter picks are not picked in the same position as you, it's not smart to play him into one of these matchups. They will most often crush Blitzcrank.
Yet, if the opposing team picks either Ziggs or Kennen, you should strongly consider selecting him, as he easily wins against these champs with win rates over 52% against both ofthem.