Multiple or dissociated selves/minds, one body. Some were intentionally written as plural rep, some were not. I mainly picked what I found relatable to my system and what other systems have recommended as good rep or relatable.
There are no genre barriers here.
I tried to avoid books where the plurality is treated by the author as an inherent problem/evil where the only solution is to be free of it.
Excluded stories where the plurality is a reveal.