Tantras (Agama & Nigama)

Mahanirvana
Kulasara
Prapanchasara
Kularnava
Rudra Yamala
Vishnu Yamala
Brahma Yamala
Tantraraja, etc.

Tantras ('looms') are divided along sectarian lines and reflect the religious beliefs and practices of medieval India. They deal with four different subjects: philosophy, yoga or concentration techniques, ritual (including the making of icons and the building of temples), and the conduct of religious worship and social practice.

Each of the Hindu religious groups has its own tradition of sacred literature, and following the three major divisions the Tantras are divided into three classes, namely:

Shaiva Agamas
Shakta Tantras
Vaishnava Samhitas

Agamas

According to the different levels of conditioned consciousness there are instructions in the Vedas for worship of different controllers, with the aim of reaching different destinations and enjoying different standards of sense enjoyment. Agamas (emanated scriptures) are books which are classified into five for this purpose:

energy - Sakti - Sakta Agamas 
visible source (Sun) - Surya - Soura Agamas 
controller - Ganapati - Ganapatya Agamas 
destroyer - Siva - Saiva Agamas 
ultimate source - Visnu - Vaikhanasa Agamas

All these form part of Veda abhyasa- the instructons on Veda.

Tantrism, which appeared from the fifth century CE- onwards, is based on mystic speculations concerning the divine creative energy. Tantrism is a method of conquering transcendent powers and realizing oneness with the highest principle by yogic and ritual means, partly magical and orgiastic in character. Tantrics believe in a strong parallelism between macrocosm and microcosm. The macrocosm is conceived as a complex system of powers which can be activated within the body of a devotee who, through the performance of the relevant rites, transforms the normal, chaotic state of his body into a 'cosmos'. 

In Tantric worship, devotees often ascribe esoteric meanings to their texts and make wide use of mantras.