Most of the vegans I know are Jains, Christians, Buddhists, Hindus, Sufis, Radhaswamis (my path), Bahais, or practice some form of individualistic "none-of-the-above" spirituality.

“Since the exterior senses, by hearing, by sight, by the sense of smell and of touch, are not able to search out the innermost mysteries of the natures, on this account God conceals within the inner members a nature having senses more subtle than all the bodies. Now because of the subtleness of its stirrings, this nature searches out the hidden wisdom of the things created by the Lord of all.” (John the Solitary, “John the Solitary On the Soul”, Syriac mystic)

In addition to the categories of apocrypha including New Testament apocrypha, as in alternative gospels and other writings of the first few centuries CE, Nag Hammadi Library and other collections or discoveries of Gnostic texts, there is another genre I’m an avid reader of: the Syriac mystics.

They’re not mystics because they write poetry,
not saints because they’re related to a saint.
Their names and costumes don’t matter;
only those who face the enemy in battle are brave.
They’re not mystics just because they play instruments
and drape an ascetic’s blanket over their shoulders,
or sing and recite scriptures.
Reading the Vedas and performing rituals
does not make them saints.
Penances, pilgrimages and living in forests
make no one a mystic.
Beads, caste marks and smeared ashes —
these don’t make a saint.
If they don’t forget the body*, says Tuka,
they’re just people of the world.

— Sant Tukarama, Many Voices, One Song, The Poet Mystics of Maharashtra

* Note: “forget the body”, or in other words, being able to transcend the material realm via a meditation practice.