I needed some dice for games that I am making. It was difficult to find free to use for anything dice icons online, so I ended up creating my own. I used Gimp to make the set. Nothing fancy, but may be useful for you. I just used a gradient fill and then put black dots on the squares for each side of the die.
[gallery ids="1515,1516,1517,1518,1519,1514" type="square" orderby="rand"]
I applied the Apache-2.0 license to these, so feel free to use or abuse them to the maximum extent possible!
http://www.mediafire.com/file/qni04n6cywtk0ed/aklu-dice.tar
Linux - keep it simple.