I use scraps, and since mostly I do quilting, most of it is quilting cotton.
I do some art quilts now and then, and some throw pillows, so sometimes things like tulle or satin or brocade make it into the quilt too. I am a rebel and I just don't care about blending things or worrying about care requirements, I'll stitch it all in and just see what happens. If something falls apart I just patch over it...it's a crazy quilt so patches blend right in!
I don't do any fancy embroidery or beadwork on mine, though. Sometimes I throw in some decorative stitches with my machine but mine are mostly just a bunch of scraps sewn down to muslin in random ways.