The greatest picks outside of lane to counter Ezreal include Nidalee, Sylas, and Lee Sin. These are all great at countering Ezreal with decent win rates over 54%. Even if these Ezreal counter picks are not picked in your lane, it's not a good idea to take him into these matchups. They will likely win against Ezreal.
Yet, if the opposite team brings either Naafiri or Maokai, Ezreal mains should seriously think about selecting him, as he easily crushes these selections with win rates over 53% against each ofthem.