Bolded is where lgbt is not main love story, in italics is stuff I haven't watched yet so i can't really give a good recommendation for it. I tried not to double what anyone said, I hope this is useful even if it is like almost several years late ^_^
Korean Movies: A Bizarre Love Triangle (Lesbian/Bi), Hello My Love (Gay and/or Bi), No Regret (Gay), Boy Meets Boy (Gay), Like a Virgin (Trans/Gay), Life is Peachy (Lesbian?)
Korean Mini-series: Lily Fever (Lesbian/Bi)
Korean Dramas: Sungkyunkwan Scandal (Gay), "It's Okay, That's Love" (Trans)