The only other texts older than the Hathapradīpikạ̄ to teach Hatha Yoga ̣ mudrās are the Shiva Samhita, Yogabīja, Amaraughaprabodha, and Śārṅgadharapaddhati [REF].
Hatha Yoga Pradipika lists 35 great yoga siddhas starting with Adi Natha (Hindu god Shiva) followed by Matsyendranath and Gorakshanath [REF].