Just found another useful website. Other than the iconfinder.net that I always use for my software projects, now I have another alternative – veryicon.com.
Veryicon.com claims itself to be “The Best Icon Search Engine”. You can search and free download Over 20,000 high quality ICO, PNG Icons for Windows, Macintosh and Linux. Using a simple test, I search for the “search” keyword to look for icons related to “search”. Suprisingly, veryicon.com returns 82 icons while iconfinder.net returns only 27 icons.
Besides the search function, you can browse icons by categories and also download the icon in packages.