From the experts:
Jocasta is a mythological name fashionably used in England, but mostly ignored here. She was the mother of Oedipus, King of Thebes, whom he (oops) unwittingly married. If you can ignore that small error in judgment, you'll find an interesting and attractive J name that's neither overused nor terminally dated.
Jocasta is also a moon of Jupiter, and a Cloud Atlas character, playing in the film by Halle Berry.