Spawn the item generator (it looks like a pet healing station). If you can find just one sample of the thing you need, you will have access to an infinite supply of it. The item generator can copy whatever you put into it, including stacks of various sizes. So if you need xithricite, for instance, then hunt some down and replicate it with the item generator. Scan and print, scan and print. One becomes two, two becomes four, four becomes eight and so on. It can be annoying to find the materials you're looking for occasionally (took me three days to find the aforementioned xithricite) but most of the time your problem will be less a matter of scarcity and more a matter of just needing a copious supply of the material in question.