Nyingma tantras

The Nyingma tradition classifies the corpus of Buddhist teachings into Nine Yanas, among the highest of which is known as Atiyoga or Dzogchen (Great Perfection). The Nine Vehicles are:

the Three Common Vehicles –

(1) Shravaka-yana, yana of the Hearers,
(2) Pratyekabuddha-yana, yana of the Solitary Realizers, and
(3) the Bodhisattva-yana, the Mahayana (consisting mainly of the sutrayana teachings taught by Buddha Shakyamuni);

the Three Outer Tantras –

(4) Kriya Tantra (Activity) Tantra,
(5) Upa Tantra (Engagement) Tantra, and
(6) Yoga Tantra (Practice) Tantra (the three stages of tantra);

and the Three Innermost Tantras –

(7) Mahayoga (primarily consisting of Utpatikrama teachings),
(8) Annuyoga (emphasizing Sampanakrama),
(9) Atiyoga (focusing on the most profound Sampranakrama).

The first three are common to all schools of Buddhism and the next three are common to all schools of Tantric Buddhism, whereas the last three are exclusive to the Nyingma tradition.