Though not strictly belonging to the stages genre, two important works in the Nyingma tradition are closely related to it. They are: (1) Longchen Rabjampa’s Mind at Ease and its commentary the Great Chariot, and (2) Dza Paltrul’s Words of My Perfect Teacher.
In both of these texts, the practices associated with the stages approach are presented explicitly as preliminaries to the instructions and practices of Dzogchen, the Great Perfection.
(Source: Dolpa. Stages of the Buddha’s Teachings: Three Key Texts (Library of Tibetan Classics Book 10) (p. 26). Wisdom Publications. Kindle Edition.)
The root text of Longchen Rabjam’s Finding Comfort and Ease in Meditation on the Great Perfection covers the following areas:
(1) Locations for Cultivating Samadhi
(2) The Meditator
(3) The Dharma to Be Practiced
In this section there are three parts:
(a) The preliminary practices:
(i) The general and specific preliminaries
(ii) The special, supreme preliminaries
(b) The main practices:
(i) The method of great bliss
(ii) The method of clarity
(iii) The method of non-conceptuality
(c) The concluding practices:
(i) Meditative experience
In his book, Mind in Comfort and Ease: The Vision of Enlightenment in the Great Perfection, His Holiness the Dalai Lama comments on this important work by the great Dzogchen master, Longchen Rabjam (Finding Comfort and Ease in Meditation on the Great Perfection).
Part Two of the book entitled, “Finding Comfort and Ease in Meditation on the Great Perfection”, has the following chapters:
(6) The Ancient Tradition of the Nyingmapas
(7) The Uniqueness of the Great Perfection
(8) The Environment and Places Conducive to Meditation
(9) The Individual Practitioner
(10) Self and Selflessness
(11) Life, Death, and Practice
(12) The Dharma to Be Practiced: The Preliminaries
(13) Bodhichitta, the Heart of the Awakened Mind
(14) Taking the Bodhisattva Vow
(15) The Empowerment of Padmasambhava and His Eight Manifestations
(16) The Clear Light
(17) A Review of the Teaching
(18) The Wisdom of Rigpa
Source: Dalai Lama. Mind in Comfort and Ease: The Vision of Enlightenment in the Great Perfection. Wisdom Publications. Kindle Edition.