Responsive Icons. Does that name ring a bell?
I designed these icons out of passion to see how the same icon concept can be presented on 16×16px, 32×32px and 64×64px grid canvas. Then I realized that they can be implemented to scale gracefully depending on the screen resolution, so the large size can be used for big resolution, the medium for tablet-like resolutions and the small one… well, you guessed it, for mobile. Nevertheless, it's a solid collection of 900 icons, using them in any way that suits you.