The cardboard tokens that come with booster boxes are pretty lame and flimsy, so I just took a few from the booster boxes I got recently and made these tokens out of them. Includes some generic ones as well like + and - for general + power and - power as well as a blank token for you to make your own.

Tokens are the same size as the cardboard ones, except they are horizontal rather than vertical. They are 3mm thick and the text is 1.5mm tall. Not only can you modify the blank model, but I've got the CAD file as well.