I've harvested lots of themed prints from scrub nurse shirts. I can get them for next to nothing and the cotton they use in them is usually the same thread count as quilting fabric. I got one that had gecko fabric and then two days later saw the same fabric posted here being sold for an arm and a leg.
I've been lucky enough to come across a few pareos (wraps) that were cotton and made with beautiful prints. If it's cotton, it's fair game.