Vast collections of translations of Mahayana sutras exist; only a small fraction of these texts are available on the web. Primary collections can be found at the following sites:
Quang Duc Buddhist
The Prajnaparamita Sutras
The Prajnaparamita or Perfection of Wisdom sutras represent a genre of Mahayana Buddhist scriptures addressing the aspiration for the perfection of wisdom. Held in the highest veneration in Mahayana traditions, there numerous versions in Mahayana countries such as China and Japan. The Prajnaparamita-Sutra is regarded as the source that feeds the bodhisattva with the amrita (nectar) of prajna (transcendental wisdom), and guides him to paramita (the other shore). It is the "utmost great perfection" which gives full enlightenment to the bodhisattva after he has successfully completed the other five paramitas: dana (charity), sila (morality), ksanti (patience, forbearance), virya (energy), and dhyana (concentration). Tibetan Buddhists believe Prajnaparamita to be the most infallible text to arouse them from the illusion of samsara (round of births and deaths).
The original sutra was expanded into larger and larger versions in 10,000, 18,000, 25,000 and 100,000 lines, collectively known at the "Large Perfection of Wisdom". These differ mainly in the extent to which the many lists are either abbreviated or written out in full; the rest of the text is mostly unchanged between the different versions. Since the large versions proved to be unwieldy they were later summarized into shorter versions, produced from 300 to 500. Shorter versions include the Heart Sutra and Diamond Sutras, widely popular sutras that have had a great influence on the development of Mahayana Buddhism (see below).
Prajnaparamita-Hridayam (hridaya means heart) -- the most condensed recension of the Sutra -- was rendered into Chinese in the year 400 AD by the famous Indian scholar and Buddhist missionary, the Venerable Kumarajiva, and even today is used as a protective spell or charm by all Buddhists of Tibet, China, and Japan, monks and laymen alike. It was translated into English by D. T. Suzuki of Japan in 1934, by Edward Conze of England in 1958, and in America by Dwight Goddard in 1969. My verbatim translation, which follows, is made directly from the original Sanskrit.
Lectures on the Heart Sutra
Sojun Mel Weitsman
Wisdom and Compassion in Limitless Oneness
Dr. Yutang Lin
The Prajna Paramita Heart Sutra
Commentary by Grand Master T'an Hsu
The Heart Sutra
Red Pine (Shoemaker & Hoard - 2004)
Essence of the Heart Sutra: The Dalai Lama's Heart of Wisdom Teachings
H.H. the 14th Dalai Lama (Wisdom Publications - 2005)
The Heart of Understanding: Commentaries on the Prajnaparamita Heart Sutra
Thich Nhat Hanh (Parallax Press - 2005)
The Diamond Sutra is probably the most popular among the texts of Prajnaparamita after the Heart Sutra, especially within the East Asian traditions of Chan, Son and Zen. The sutra's primary themes are the realization of the illusory nature of all phenomena and the theme of non-abiding. "Non-abiding, in a Buddhist, and especially a Chan context, refers to the continual practice (i.e., not just while one is sitting in zazen) of being aware of the stoppings and goings of the mind, and avoiding being tricked and ensnared by the web of mental constructs that one continually weaves for oneself. The ongoing proliferation of these deluded constructs has as its causes and conditions not only in the thought processes in which one is engaged at the present moment, but also the flowing river one's entire multi-lifetime load of previous karma." (Charles Muller - see below )
The Diamond Sutra
Translation - Charles Muller
The Diamond Sutra
Plum Village Chanting Book
The Diamond Sutra
Red Pine (Counterpoint Press - 2002)
Buddhist Wisdom: The Diamond Sutra and The Heart Sutra
Edward Conze (Translator), John F. Thornton (Editor) (Vinatge - 2001)
The Diamond That Cuts Through Illusion: Commentaries on the Prajnaparamita Diamond Sutra
Thich Nhat hahn (Parallax Press - 2005)
The Diamond Sutra: Transforming the Way We Perceive the World
Mu Soeng (Wisdom Publications - 2000)
An encyclopedic work of Mahayanist thought and practice, including the bodhisattva vows, discipline, and compassion. Bodhidharma, the founder of Zen, based his teachings on the Lankavatara Sutra.
The most important doctrine issuing from the Lanka is that of the primacy of consciousness, often called simply "Mind Only", meaning that consciousness is the only reality. The sutra asserts that all the objects of the world, and the names and forms of experience, are merely manifestations of the mind. It is the erroneous concept of subject/object that ties us to the wheel of rebirth.
The Lotus Sutra is a large Mahayana scripture which scholars today seem to feel was compiled in four strata, between sometime in the 1st century B.C.E. and about 150 C.E. in India. Written originally in Sanskrit, the sutra was translated several times into Chinese in the 3rd to 5th centuries C.E, with the most famous and highly regarded of these translations by Kumarajiva (died c. 406 C.E.), who translated a great number of other Buddhist sutras and writings as well. Most if not all of the English translations currently available are based upon Kumarajiva's translation.
The Lotus Sutra emphasizes devotion and faith, noting that the path to buddhahood is not restricted to those who practiced monastic austerities but to those who worship the buddha (or buddhas) in a number of ways. In China, the Lotus Sutra was elevated to most-favored-sutra status and was transmitted to Japan by the Japanese monk, Dengyo (Saicho) in the 8th century C.E. and soon became the most revered sutra in that land.
Sutra of the Lotus of the Wonderful Dharma
Translation - Burton Watson
Inside the Lotus Sutra
Stephen L. Klick
Zen and the Lotus Sutra
Ryuei Michael McCormick
Opening the Heart of the Cosmos: Insights on the Lotus Sutra
Thich Nhat Hanh (Parallax Press - 2005)
The Lotus Sutra
Burton Watson (Columbia University Press - 1993)
Generally considered to be the most complete teaching concerning the mind in the Mahayana Canon. According to tradition, the sutra was translated in 705. Its main themes are importance of meditational ability (samadhi) and the importance of moral precepts as a foundation for the Path.
Shurangama Sutra: Text, Commentaries, and Articles
Da Fo Ding Shou Leng Yan Jing (Compiled by Ron Epstein)
The Surugana Sutra
Master Sheng Yen (Dharma Talk, Chan Magazine)
The Shurangama Sutra: Sutra Text and Supplements Only
Hsuan Hua (Buddhist Text Translation Society - 2003)
Vimalakirti Nirdesa Sutra
Sometimes referred to as the "crown jewel of the Mahayana" and regarded as the main Sutra on non-duality. In the sutra, the layman bodhisattva Vimalakirtu expounds the doctrine of emptiness in depth to the Buddha's main disciples. The sutra is notable for the liveliness of its episodes and frequent touches of humor, rarities in a religious work of this type. Because the sutra centers on a lay person, and because of its enduring literary appeal, it has been particularly popular among lay Buddhists in China, Japan, and the other Asian countries where Mahayana doctrines prevail, and has exercised a marked influence on literature and art.
A Talk On The Vimalakirti Sutra
Hisamatsu Shin'ichi Preface
Vimalakirti's Gate of Nonduality
John Daido Loori, Roshi - Dharma Discourse
The Phenomenal Universe of the Flower Ornament Sutra
Though not widely known, the Huayan, or Flower Ornament Sutra, has had a lasting impact on the way Zen and Chan Buddhism are practiced.
Taigen Dan Leighton
The Great Flower Garland Scripture of the Buddha's Expanded Mahayana Teachings
Buddhist Text Translation Society
Caught in Indra’s Net: the Huayan Sutra
Robert Aitken Roshi