Locations, people, conversations, something else?
For me it's recalling people that were in my dream.
Usually I can't recall who I dreamt of specifically so I refer to them as "one of my friends" or "man/woman" in my DJ.
The only exception are the members of my family.
Last night I dreamt my girlfriend died and upon waking I wasn't sure if it was my current gf, a previous one or my imaginary/dream gf.