The gods, the Rishis and the Siddhas become visible to him who is given to study, and they do take part in his work.
The Narada or Naradiya Purana is where Narada has described the duties which were observed in Vrihat Kalpa , that is called Naradiya, having twenty five thousand stanzas....It is communicated by Narada to the rishis in Naimisharanya, on the Gomati River.
Jain myths and legends incorporate the names of Hindu rishis and deities, and Jainism has its own version of Ramayana and Mahabharata.
Sage Vyasa is known as Veda Vyasa, as he classified and compiled together, the vast body of Vedas or mantras then existing. He classified the Vedas in four, namely Rig , Yajur, Sama and Atharvana and taught them respectively to four great rishis – Sumantu, Vaisampayana, Jaimini and Paila.
After gradual research; I have come to the conclusion that long before all heavenly books, God had revealed to the Hindus, through the rishis of yore, of whom Brahma was the Chief, His four books of knowledge, the Rig Veda, the Yajur Veda, the Sama Veda and the Atharva Veda. The Quran itself made veiled references to the Upanishads as the first heavenly book and the fountainhead of the ocean of monotheism.