Any yarn and needle size can be used - the pattern gives instruction on how to work with any gauge you want to produce pretty much any size of d-4 shaped bag.

Can easily be converted into a stuffed toy by stuffing and seaming instead of adding a zipper.

It its heart, these are really just instructions on how to do the math needed to knit an equilateral triangle of any size in any gauge, so it should work equally well for a d20 or a d8 just alter the number of triangles you are making, the places you put the numbers, and then sew them together accordingly - the best way to get it right is to use a die as your guide and copy from there.