I'm looking for dramas where the leads fall or are deeply interested in the other before meeting in real life. 

A few I have seen that fit are:

Love Me, Love my voice    Both leads seemed to fall for the other voice before they ever meet in real life

Everyone loves me  Male lead falls for a female friend who plays games with him

A Boss and a Babe Was interested from the start as he listened to the other's ASMR channel

Lost Romance - fl has a crush on ml before meeting him 

  • Perfect Marriage Revenge - ML loves FL's painting and becomes interested in her as a result
  • Dear Diary - FL "created" ML as her ideal man/crush in a book she wrote as a kid before she meets him as an adult
  • Dramaworld - FL has a crush on the actor ML from watching his shows
  • Metaverse - ML is a video game character who FL is very attached to before she enters the game and meets him

not a drama but a movie Haru

  • W - The ML is the main character in a manhua series published by the FL's father. The FL is invested in him before she is pulled into his world and meets him.
  • City Hunter - The ML becomes interested in the FL because of a picture of her that he grew up with.
  • The King: Eternal Monarch - The ML is interested in + spends years looking for the FL because her ID badge connects her to an important event in his childhood.
  • To the Beautiful You - The ML is a high-jump athlete and the FL is his fan. 
  • My Dearest - The FL has a recurring dream of her true love, but when she meets the ML she doesn't realize he's literally the man from her dreams.