The cheerleader effect without a doubt.
Let me explain. When a bunch of attractive people are together, it makes them all look even more attractive than they actually are.
Taking the name of this effect as an example, each member of a group of cheerleaders or "cheerleaders" enhances the beauty of the others, making them prettier or prettier.
Amazingly, the term became popular thanks to the series "How I Met Your Mother". And it caused such a stir that it was the subject of study in 2013.
They picked up the participants and took individual and group photos of them. The results almost always showed that they looked better in a group.