The greatest picks out of lane to counter Samira include Naafiri, Rengar, and Lee Sin. These champions are all good at countering Samira with win rates over 59%. Even if these Samira counter picks are not taken opposite your position, it's not a good idea to play her into any of these matchups. They will often win against Samira.
Yet, if the opposing team picks either Galio or Kennen, you should seriously consider selecting her, as she easily crushes these selections with win rates over 54% against each ofthem.