It will cut basically any fabric. I have used it to cut synthetics (polyester) and I've cut heavy cotton with it. The hardest materials to cut are white fabrics as they reflect a lot of light, but you can always go slower. It can take a while to cut a large white thick cotton piece though. If that was desired it would make sense to go for a slightly higher powered laser module if one was available.
The burned edge for synthetics is itchy. You can either design the garment to hide that edge from skin contact, or design your cuts to be a bit large and then snip off the edge that would be in skin contact (beats manually tracing out the entire pattern). The burned edge for cotton is nicer.
