These are some of my favorite stitch markers ever. Infinity Ring Knitting Stitch Markers from Twice Sheared Sheep.
DIY: Stitch markers for yarn lovers (beads and twisted wire) from Miss P. http://portialawrie.blogspot.com/2013/01/diy-stitch-markers-for-yarn-lovers.html
Stitch markers--made with just a few beading supplies
Weaver's knot, helpful with yarn color changes
Perfect for graphghans.
Delights-Gems: Let's Make Stitch Markers!!!
Rain Snag Free Knitting Stitch Markers Small Fit by HeidiandLana