There are 18 Mahapuranas (great Puranas) in Hindu tradition, along with 18 Upapuranas (minor Puranas), totaling 36 major Puranic texts. The Mahapuranas include famous texts like Bhagavata Purana, Vishnu Purana, and Shiva Purana. These texts contain narratives about gods, cosmology, and genealogies. The number 18 is significant in Hinduism - also the number of chapters in the Bhagavad Gita.