Any shows where the female lead loves a man who is either out of reach or died. She then runs into the male lead who is the spitting image of the other guy and decides to fall for him because of who he looks like. Eventually she falls for him for real, but the real reason she pursued him is still looming. He finds out and gets mad. She convinces him she loves him for real now and they get back together.

I only know ones where it is the female that has a doppelganger 

The only male twins dramas i know of, but these are not really that type of plot you are looking for:

  • Cinderella man
  • Resurrection
  • Mars
  • persevere go haera
  • Non romance, and more suspense thriller: Circle, Duel, Yasha, sirius

For that plot, there are tons of twin girls stories:

  • What planet are you from
  • Mina
  • good witch
  • Not quite like the whole plot: school 2015 who are you, i have a lover



But how about a movie? The nearest i can think of is a movie with Yoo Jitae titled Secret Love.

I know of female lead doppelganger. I really liked Bride of the Century, it has FT Island's  Lee Hong Ki in it.

These both are about males!!

  1. Revive
  2. Last-minute-romance

These both are about male and female!!

  1. Drama-special-series-season-1-dream-of-400-years
  2. The-journey (Both seasons)

These both are about females!!

  1. Karn-la-krang-neungnai-hua-jai
  2. Love-in-time