As much as I was never a fan of Scooby Doo, I have to admit Daphne and Velma probably have the best chance here. As mentioned, Betty is an athlete, but I've never seen brawling as really her or Veronica's thing. AFAIK, Velma's not an athlete herself, but she and Daphne have been in their fair share of danger being in Mysteries, Inc.
If we count Buff -- I mean Daphne from the live action films, then she soloes.