There are many fine examples of early Buddhist teachings that were never preserved in the Pāḷi Canon, or its commentaries, and recently I have been translating some of them including Arthaviniścaya, An Analysis of the Topics and Dhamma-Saṅgraha, The Dharma Collection.
One of the most interesting texts containing material from the early tradition is Lalitavistara (An Elaboration of the Play (of the Buddha’s Life), which is believed to be an expansion (vaipulya) of an earlier Sarvastivāda work (for more information on this text see Nariman’s appraisal).
This text preserves a teaching given by the Bodhisattva in Tuṣita Heaven before he descends for his final life, which outlines – and anticipates – certain basic teachings the Buddha will give after he has awakened.
These 108 entrances into the light of the Dharma show how the development of certain qualities leads to, or opens the way to, certain other desirable and necessary qualities for the fulfilment of the path, and include mention of the thirty-seven things on the side of awakening (Sapta-triṁśad-bodhi-pākṣikā dharmāḥ), which is found in many places in the early tradition.
The text was edited by Prof. Dr. S. Lefmann in 1885, and the only translation I know of directly from the Sanskritised Prakrit text is the one by Bijoya Goswami, which is unfortunately inaccurate in many respects. I hope this new translation will help bring to notice this neglected teaching which acts as a good summary of the teaching of the Buddha.