I've made a few scrappy quilts. One was scrappy with Civil War type fabrics. Anything batik or bright would not have looked at home in that quilt.
Another time, I found a great pattern that had me separate my scraps into lights, mediums, and darks, and then I sewed them together in five types of pairings: light to light; light to medium; medium to medium; medium to dark; and dark to dark. The shift in values made for a phenominal quilt. If there was a fabric that I couldn't classify as either light, medium, or dark (ex. big pink flowers on black) I didn't use it in that quilt.