Who was the Buddha's foremost female disciple in psychic powers?

Uppalavanna was the Buddha’s foremost female disciple in psychic powers.

Uppalavanna was a Buddhist nun and one of the Buddha’s two chief female disciples, the other being Khema. Her name means “the color of a blue water lily,” a reference in Buddhist tradition to her unusual complexion. She was associated with Savatthi and entered the monastic order rather than marrying one of the many wealthy suitors attracted to her beauty.

According to Theravada accounts, Uppalavanna attained arahantship less than two weeks after ordination. She used a fire kasina—a meditation object based on a flame—to develop deep concentration and insight. After enlightenment, she became renowned for mastery of iddhi, or extraordinary spiritual powers.

Khema is often confused with Uppalavanna because both were chief female disciples. Their special distinctions were different: Khema was foremost in wisdom, while Uppalavanna was foremost in psychic powers. Her male counterpart in this category was Maha Moggallana, who was likewise celebrated for supernatural abilities.