Crisp Icon Set is a set of 108 pixel perfect vector icons that come in 3 different sizes, 16×16, 32×32, and 48×48. These are entirely vector and all of the icons can literally be scaled to any size if needed, just keep the aspect ratio when resizing to keep them pixel perfect.
It includes a Photoshop PSD, a retina version, a CSH (custom shape) file, and the PNG icons!