A classification of Tantric texts on the basis of the three currents of Tantric tradition daksina, vama and madhyama is also found each of which is again subdivided into two classes, inner (harda) and outer (bahya). This division is also made in terms of divya, kaula and vama. The amnaya divisions, six or nine, of the regions are often brought under two general categories Kadimata and Hadimata. There is also a tradition of classifying Tantras into astaka, mangala, cakra and sikha. Tantric texts are known by such names as Tantra, Upatantra, Agama, Samhita, Yamala, Damara, Tattva, Kalpa, Arnava (ka), Uddala, Uddisa, Upasamkhya, Cudamani, Vimarsini, Cintamani, Purana, Upasajna, Kaksaputi. Kalpadruma, Kamadhenu, Sabhava, Avataranaka, Sukta, Amrta (tarpana), Darpana, Sagara, etc.
The terms Tantra, Agama and Samhita are very often used in the same sense, each of which denotes any type of religious text. According to Pingalamata Agama is that by which the objects around are known. The name is also explained as that class of Tantra which is addressed to Parvati by Siva. It is said that the word is formed by the first letters of agata (that which comes from Siva), gata (that which goes to Parvati) and mata (that which is established). It is called Agama because knowledge proceeds from it, Sastra because everything is controlled and protected by it, Jnana because everything can be known through it, and Tantra because everything is preserved and perpetuated by it. According to the Varahitantra, Agama deals with seven topics, viz., cosmology, destruction, worship of god,sadhana, purascarana, six forms of rites and four forms of meditation. The number of Agamas of the Pancaratra school is generally stated to be 108, but on comparison with different lists their number appears to be more than 200. The basic Saiva Agamas are 18 in number according to one tradition, and 28 according to another. Other sects have their own Agamas also.
The Varahitantra gives a list of twelve special Agamas which are Muktaka, Prapanca, Sarada, Narada, Maharnava, Kapila, Yoga, Kalpa, Kapinjala, Amrtasuddhi, Vira and Siddhasamvarana. Another class of Tantric literature is called Damara which traditionally consists of six texts known as Siva, Yoga, Durga, Sarasvata, Brahma and Gandharva. Yamala is a special class of Tantric literature, the principal ones being eight in number: Rudra, Skanda, Brahma, Visu, Yama, Vayu, Kubera and lndra. Two other old texts Pingalamata and Jayadratha belong to the Yamala group. Besides there are other Yamalas like Aditya and Ganesa.
An ordinary Tantra has a form somewhat similar to that of a Purana, since it theoretically discusses in order the same five subjects (pancalaksana): the creation and dissolution of the universe, the worship of gods, the attainment of supernatural power, and union with the supreme being. But here the mythological elements are absent. Instead we find details of ritual acts and practices which remind us of the contents of Brahmana literature. We have Tantric parallels of all Smarta and Puranic rites. A fourfold division of Tantra topics into Vidya, Kriya, Yoga and Carya is indicated in many texts. In some cases Yoga and Carya are indicated in many texts. In some cases Yoga and Carya have been substituted by Upaya and Siddhi. There is also a twofold division into Kriyatantra and Yogatantra.
In a good number of Puranic texts Tantric subjects have been incorporated. Apararka quotes a passage from the Devipurana wherein the qualification of a Sthapaka, i.e. one who performs the installation of God, is considered in terms of his ability in Tantric rituals. The Kalikapurana devotes many chapters to the description of mantras, mudras, kavacas, nyasas, etc. The Agnipurana states that the worship of Visnu and other gods should follow the Vaidiki, Tantriki or Misra way, the first and third being for the higher varnas and the second or Tantriki for the Sudras. The Bhagavatapurana mentions Tantric cults of Visnu, Vaidiki and Tantriki diksa, Tantric methods of angas, upangas, ayudhas, etc. Many Tantric elements are found in the medieval Nibandhas.