Depending upon the exact ethos of your vegans, they can still use leather and bone from natural kills. They become scavengers instead of hunters. They may learn where the local predators hunt, wait for them to make a kill and eat their full, then move in to strip the carcass of remains. Such a culture would have a problem with outsiders offering them animal products and swearing that they were natural kills; so I think there would be an emphasis on such items having to be acquired by the owner themselves so the provenance is known.
Notably, they might harvest from their own kinsmen when they die — vegans largely object to taking from animals because consent cannot be obtained. But humans could leave their corpse to the next generation to use. There are several examples of this sort of practice in human history. Although (although, all of them were religiously inspired, vegan inspired, so far as I know).