So, I bought a bunch of coloured wooden beads and jump rings with the idea that I'd make my own. Making stitch markers of this kind is super easy. Simply place a bead onto a small jump ring, which you then attach to a larger ring.
As we are wont to do, my daughter and I set up a little production line. We made markers upon markers, and even a little shawl pin, that you can just about make out in the picture.