Few anime subgenres are as distinctively niche as harem anime, where seemingly everyone is in love with the show's protagonist. Traditionally, this has been a young man surrounded by beautiful women, as in Tenchi Muyo!, but "reverse harems" like Ouran High School Host Club are some of the most popular examples of the subgenre.
Source：https://www.cbr.com/best-harem-anime-myanimelist/
