I agree with Jim Smith,

Many man-made materials are re-purposed from what they were originally marketed for. A walk through any of the Big Box stores will always be worth the trip. Now that being said, there are many man-made products that have been re-designed to meet the needs of fly tyers. Many of the original products will still stand the test of time. I saw something at JoAnne's Fabrics today that forced a light bulb to go off in my head. I did not buy it and regret not bringing it home. Next weekend I shall correct my mistake and see if I can adapt something new to my flies.