About anything will work as long as it's not really soft. I try to use something that either matches or contrasts with the rest of the bow. I've used walnut, osage, purpleheart, zebrawood, burl maple, padauk, desert ironwood, deer/elk/moose antler, buffalo and cow horn, and probably other stuff that I don't remember. The only thing I tried that seemed too soft was mahogany.