In Abhodah Zarah (26b, Tosephoth) it says: "Even the best of the Goim should be killed"

Comment. This is incorrect. The phrase occurs, not in the Avodah Zarah, but in Soferim 15:10, in the following context: "Yoḥai taught: Kill the best of the heathens in time of war; crush the brain of the best of serpents. The most worthy of women indulges in witchcraft. Happy is he who does the will of the Omnipresent."