Buddhist tantric literature
Buddhist tantric literature refers to the vast and varied literature of the Vajrayāna (or Mantrayāna) Buddhist traditions. The earliest of these works are a genre of Indian Buddhist tantric scriptures, variously named Tantras, Sūtras and Kalpas, which were composed from the 7th century CE onwards.
Source: Wikipedia — Buddhist tantric literature (CC BY-SA 4.0)