A collection of series set in a world where beauty standards are the opposite of ours. So ugly equals beautiful and vice versa. Like in 'The Twilight Zone's episode 'Eye of the Beholder'.... more>>

In most cases the protagonist gets Isekai'd to this world and builds a harem of "ugly" girls. The heroines are often discriminated against for their looks and thus have have low self confidence or in some cases mental health issues. So there's a wholesome/white-knight aspect. <<less