i see dead people

fl has been able to see ghosts all her life

ml starts seeing ghosts after an accident where he narrowly escapes death

fl is originally blind, but gets eye surgery, and starts seeing ghosts after the fact

mc starts seeing ghosts after his sister accidentally does something... sorry, it's been a while lol. iirc, this shows more of him hearing the ghosts rather than seeing them.

haven't seen this one, but ml can see ghosts

haven't seen this one either, but it's based on the kdrama above

mc has been able to see ml, who is a ghost, since he was a kid