I just use a regular ruler to cut odd shape scraps into usable sizes. I don't worry about the bias. ones like you describe can be used in crumb quilting
http://quiltville.blogspot.com/2005/...bs-crumbs.html
Or you can try your hand at a bottled rainbows quilt
http://www.stitchedincolor.com/2011/...ape-quilt.html