Voidcraft 2.1 includes productivity runes. This is a new feature that I initially wasn't sure if it was even needed, because voidcrafting has no inputs, so increasing the speed also increases the products you get. I decided to add it because a productivity bonus, unlike speed, also uses less input resources, such as void flux. I'm still tweaking the balance; a productivity rune is not going to be as good as an equivalent speed rune, but (unlike productivity modules) it doesn't include a speed penalty. Productivity runes are only usable in recipes where they would matter, so normal voidcrafting (with zero inputs) won't use them.