Thea

A fictional bearer is the secondary main character from Hayao Miyazaki's graphic novel "Shuna's Journey," an enslaved teenage girl who helps the protagonist after a long and dangerous voyage.

Thea is a supporting character in the musical Spring Awakening. She is among the group of girls who spend time with Wendla, the female lead.

I’m surprised, and kind of disappointed nobody mentioned the Thea Sisters books.

Thea Dearden Queen is a fictional character from the TV show Arrow, which is based on DC Comic's Green Arrow. She is the sister of protagonist Oliver Queen, and daughter of Moira Queen and (SPOILER) Malcolm Merlyn. She goes by the alter ego "Speedy".
Thea is portrayed by actress Willa Holland.

Thea Gilmore is a British singer and musician.

A famous bearer was German writer Thea von Harbou, who wrote the movies "Metropolis", "M", "Der Mude Tod", and the "Dr. Mabuse" films.

In Alma Alexander's books, 'World Weavers', the main character is a girl named Thea, which is short for Galathea. In the book, Thea is the seventh child in her family. And her parents are both seventh children too, so Thea is known as a Double-Seventh. In the magical world, much is expected of her even though she can't get any magic right at all. Thea struggles a lot, but discovers herself in the end.

A famous bearer of this name is Canadian actress Thea Gill, whose first name is pronounced TAY-ah (TAY, rhymes with "ray").