Over at Spoonflower I’ve posted 14 celtic knotwork designs which you can buy there on a whole bunch of fabrics, on wallpaper, or on giftwrap.
There are some all-over repeating patterns, some panels with bold knotwork stripes, some more painterly work (hint:drapes), and a couple of stitch-them-yourself banners (seen below) with my crazy Celtic pirate flag and the Chaos Star.