Hi NOMIOMI. The icons that you see are not from any icon set. The way I have done these is first to search on Google for icons that I like (Royalty free ones) be it the background for an icon (the silver box) or the actual icon itself (eg. the opera one) and edit in gimp, to make the icons look the way I wanted. I don't know how to use Gimp properly yet, to make a complete icon and then a whole set, so I have to do it this way for the time being.