It depends entirely on what you want to do with the quilts you might use them on. Many art quilters use Prismacolor pencils, oil pastels, colored markers, crayons, and even pastels on fabric. All can be sealed with one type of acrylic medium or another to make them more stable, though none are suitable for heavily washed bed quilts. It's easy enough to find examples online and then decide if you'd like to try something similar. It's quite fun actually.
