We now have 15mm x 4mm Discs in our online parts shop! They are made of wood, measure 15mm x 4mm, and are available in 7 colors. We continue to add more variations of the discs because they are such a generically useful piece to so many game designers.
Get them at https://www.thegamecrafter.com/game-pieces?q=disc%2015mm%20x%204mm&hPP=2...