Saptarshis

Visvamitra

Visvamitra also known as Brahmarshi or Rajarshi because of him being a successor to King Kusha, He gave up on his inheritance to tread the path of Exploration in quest of Knowledge. He is known to have Authored most parts of Rigveda Including Gayatri Mantra.

Jamadagni

Gautama

Vashistha

Kashyapa

Bharadwaja

Atri

Special Mention Charvaka and Kanad