6 verses have
best
in Edition Clear Qur'an by Talal Itani / Al-Kahf (The Cave)

18:7We made what is upon the earth an ornament for it, to test them as to which of them is best in conduct.

18:19Even so, We awakened them, so that they may ask one another. A speaker among them said, “How long have you stayed?” They said, “We have stayed a day, or part of a day.” They said, “Your Lord knows best how long you have stayed.” “Send one of you to the city, with this money of yours, and let him see which food is most suitable, and let him bring you some provision thereof. And let him be gentle, and let no one become aware of you.”

18:21So it was, that We caused them to be discovered, that they would know that the promise of God is true, and that of the Hour there is no doubt. As they were disputing their case among themselves, they said, “Build over them a building.” Their Lord knows best about them. Those who prevailed over their case said, “We will set up over them a place of worship.”

18:22They will say, “Three, and their fourth being their dog.” And they will say, “Five, and their sixth being their dog,” guessing at the unknown. And they will say, “Seven, and their eighth being their dog.” Say, “My Lord knows best their number.” None knows them except a few. So do not argue concerning them except with an obvious argument, and do not consult any of them about them.

18:26Say, “God knows best how long they stayed.” His is the mystery of the heavens and the earth. By Him you see and hear. They have no guardian apart from Him, and He shares His Sovereignty with no one.

18:44That is because authority belongs to God, the True. He is Best in rewarding, and Best in requiting.