I use my "Fingerguard" (which are no longer made
) 6" x 12" and 6" x 18" almost exclusively. I just bought a 3" x 18" ruler to help with a WIP that calls for 3" squares. I have some square rulers that I sometime use. I don't use or buy specialty rulers, I just stick with the basics. I have some Omnigrid, some Fons & Porter and some Creative Grid squares.