The six orthodox schools are called as shatdarshanas and include Nyaya, Sankhya, Yoga, Vaisheshika, Purva Mimamsa, and Uttara Mimamsa (Vedanta Philosophy). Most of these schools of thought believe in the theory of Karma and rebirth.
What are the principal texts of each school of philosophy and interpretation here? (Just like Upanishads and Vedas for Vedanta) - Their foundational texts?
As far as I know, I can recall only Yoga Sutras of Patanjali in Sankhya school of philosophy as a fundamental text.