WebDesignShock has recently released a high-quality set of interface icons that follow the style of the ones used in Google+.
There are 204 items in the set, they have gray and colored versions (great for hover effect) and come in 2 sizes: 18*18px and 128*128px. That’s not all, besides .PNG, the icons are also available in .PSD format.
It has almost every item that a web application can need from actions to charts or devices. Simply, a must-bookmark.