From Rigpa Wiki
Niguma (Wyl. ni gu ma) (b. 10th century) — an Indian yogini who is said to be either the sister or consort of Naropa. After having reached the tenth bhumi and achieved rainbow body, she could directly receive teachings from Vajradhara. She transmitted her six yogas, the Six Yogas of Niguma, to Khyungpo Naljor who founded the Shangpa Kagyü lineage.
- Sarah Harding, Niguma, Lady of Illusion (Ithaca: Snow Lion, forthcoming November 2010)