Thea is a diminutive of names ending in -thea, including Dorothea, Althea, and Anthea. It is also the Anglicized spelling of Theia, the Titan of sight, goddess of light, and mother of the moon. She was the consort of Hyperion, and mother of Helios, Selene, and Eos.

Theon, an ancient name attached to a noted Greek teacher of mathematics and astronomy, also father to the first woman mathematician, might appeal to parents in this field. You can think of Theon as Theo with something a little extra.

Selma has recently been given a more youthful spin via actresses Selma Blair and Salma Hayek. But while Selma has not yet become popular again in the US, it is widely used in both Sweden and Norway.

Theia is the Titan of sight and the shining light of the clear blue sky. She is the consort of Hyperion, and mother of Helios, Selene, and Eos. The name is more familiar in its Anglicized version, Thea.

A solid, if somewhat serious Greek name. Theoni and Theona are variants. This might be a possibility if you're looking for an unusual route to Thea.

A unisex name used in India with a virtuous meaning.