Hmmm...
Lasair is a Celtic goddess who became an Irish saint, as did Brigid/Brigitte...
Niamh is a Celtic goddess, queen of the land of Eternal Youth, but nobody will ever pronounce it right.
Rhiannon is a Welsh goddess from the Mabinogion.
Aglaia means beauty in Greek. She's one of the three Graces.
Ligeia is one of the sirens. Leucosia and Thelxiope too.
Deianira was a wife of Herakles (Hercules).
Lavinia was the princess of Latium and the second wife of Aeneas
Sybil was a prophetess from the Aeneid (and ither stuff).
Niara is a name I made up. Kinda catchy though.
Moira is the singular form of "The Fates" from Greek myth
Atalanta was a Greek heroine, though may sound too much like Atlanta.
Aoifa was a Celtic shadow-amazon/warrior-woman.
Calliope, Clio, Terpsichore, Urania, Euterpe, Thalia, Melpomene, Erato, Polyhymnia, the nine Muses, although some of those aren't such good names...
Themis the Titaness or the similar Thetis, the nereid mother of Akhilles.
Eurynome, a Pelsgian creator-goddess who became an oceanid in classical Greek myth
Ishtar is a Babylonian goddess of beauty/war, and Inanna is the Sumerian equivalent.
Helen was a pretty famous Greek girl, and her mother was Leda.
And so many more!