I guess it depends on when and where the characters come back, which is such a closely guarded secret that I haven't even seen fake leaks that mention them, let alone the real ones.
Among those characters, the character I'd most like Carol to meet is (of course) Wanda (not getting my hopes up there, though; if the comics don't know they're friends, the movies probably don't). But Spider-Man is up there, particularly since they're both in the "got powers by accident" club, and it isn't as big in the MCU as it is elsewhere.