Important texts of the Vedic period include the six Vedangas and the four Sutras. The six Vedangas, which means the limbs of the Vedas, are, shiksha (study), vyakarna (grammar), nirukta (lexicon), jyotisha (astrology), and kalpa (methodology of rituals). The four Sutras are Shrauta ( on how to perform rituals), Sulba (on how to build altars), Grihya (on how to perform domestic rites) and Dharma (on how to live life according to ones dharma).
The Puranas are a strange combination of mythology and history freely inter mixed. They form the smriti tradition, that is those, which are remembered. They are essentially narrative accounts of various gods, sages and ancient kings of immense repute. They also describe the process of creation and the struggle between the good and evil forces of the universe.
The Darshanas which are six in number, namely, the Uttara mimansa, the Purva mimansa, Samkhya, Yoga, Vaisheshika and Nyaya Darshanas. together they constitute the six schools of ancient Hindu philosophical thought.
A study of them provide immense insight into ancient Indian thinking and its evolution into a complex body of schools and philosophies.
The Bhagwat Gita contains the teachings of Lord Krishna to Shri Arjuna in the middle of battle field about the meaning of true self, renunciation of work, the true nature of karma, the three qualities, the true nature of God, the definition of a true devotee and so many other things.
Hinduism was also greatly influenced by the works of later day scholars such as Shri Shankaracharya who provided commentaries on many Upanishads, brought the Vedic knowledge back to the forefront through his various works and tireless efforts and breathed life into sagging traditions.