Rule the world- Historical, is not time travel but it has a fun spin since the story is supposed to be a book that is being written.
Sungkyunkwan Scandal- Only two guys after her but there are so many around her that it feels like a reverse harem.
Hwarang- Again it's a love triangle but there are so many guys...
The Flame's Daughter- Everyone and their aunt is in love with the FL.
Oh! My Emperor- Season 1 and 2, there are lots of male leads and they each represent a zodiac sign, not all of them are in love with FL but there are just so many handsome guys. They are part of a irl boy band btw.