When they came, he looked on Eliab and thought, “Surely the Lord's anointed is before him.” But the Lord said to Samuel, “Do not look on his appearance or on the height of his stature, because I have rejected him. For the Lord sees not as man sees: man looks on the outward appearance, but the Lord looks on the heart.” - 1 Samuel 16:6-7

It's a really strange detail when the Holy Spirit points out how attractive certain people are. It seems frivolous and banal to describe a biblical figure that way, but beauty comes from God and is used for or against Him in various accounts given in Scripture.

I am only including instances when the Holy Spirit directly calls someone attractive. Eliab is described as looking downright princely by Samuel, but the Holy Spirit includes no confirmation of his looks, even going so far as to record the Lord's command to ignore his outward appearance. In contrast, the Holy Spirit provides descriptions of certain other people's outward appearances that command attention, like when He called Saul the tallest and most handsome man in all Israel.

Accounts in Scripture

Rebekah

The young woman was very attractive in appearance, a maiden whom no man had known. - Genesis 24:16

Saul

And he had a son whose name was Saul, a handsome young man. There was not a man among the people of Israel more handsome than he. From his shoulders upward he was taller than any of the people. - 1 Samuel 9:2

David

And he sent and brought him in. Now he was ruddy and had beautiful eyes and was handsome. And the Lord said, “Arise, anoint him, for this is he.” - 1 Samuel 16:12

Absalom

Now in all Israel there was no one so much to be praised for his handsome appearance as Absalom. From the sole of his foot to the crown of his head there was no blemish in him. And when he cut the hair of his head (for at the end of every year he used to cut it; when it was heavy on him, he cut it), he weighed the hair of his head, two hundred shekels by the king's weight. - 2 Samuel 14:25-26

Abishag the Shunammite

So they sought for a beautiful young woman throughout all the territory of Israel, and found Abishag the Shunammite, and brought her to the king. The young woman was very beautiful, and she was of service to the king and attended to him, but the king knew her not. - 1 Kings 1:3-4

Adonijah the son of Haggith

His father had never at any time displeased him by asking, “Why have you done thus and so?” He was also a very handsome man, and he was born next after Absalom. - 1 Kings 1:6

Vashti

to bring Queen Vashti before the king with her royal crown, in order to show the peoples and the princes her beauty, for she was lovely to look at. - Esther 1:11

Esther

The young woman had a beautiful figure and was lovely to look at - Esther 2:7