A large tom cat, especially if your cat is female and not spayed. Or two tom cats fighting over a female cat.
Doubtful but possibly a racoon. Racoons are known vectors for rabies.
Anything bigger than a racoon would, I think, mean significant injury or death (life a fox or wolf).
Where do you live, i.e., rural, city?
How is your cat reacting? I would be very afraid of infection.