>>13856013The Gospel of Thomas, The Gospel of Judas, The Apocalypse of Adam, The Apocryphon of John & the Gospel of Mary Magdalene are all excellent reads along with any other texts in the Nag Hammadi Library. If you want a good starting point for Gnosticism I recommend Gnosticism: New Light on the Ancient Tradition of Inner Knowing by Stephan A. Hoeller. It goes through the Basics and the Gnostic creation myth and how Gnosticism has changed through Antiquity to the Modern era.