Scrappies are my hands-down favorite! The more fabrics, the better. And they don't ever have to look random or haphazard, unless that's the way you want them to look. You can make any pattern you like into a scrappy.
One of the first quilt books I ever bought was by Judy Martin, The Grand Dame of scrap-quilting, IMHO, before Bonnie Hunter came along: Scraps, Blocks and Quilts. I think that one is out of print, but I now own several of her books. I bet your local library would have some. She is more old-school, but has some really inspiring ideas.