Not sure about a game engine (editor?) but one has to be a lot more careful with using stock icons for a typical desktop app than they would with a web app. It

Not sure about a game engine (editor?) but one has to be a lot more careful with using stock icons for a typical desktop app than they would with a web app. It's easier to retrofit an icon set into a website (where you’re expected to come up with your own aesthetic) than it is to retrofit it in a desktop app (where you’re expected to follow certain metaphors and not deviate your appearance too much from the rest of the system). I’ve been seeing a lot more OSX apps lately use the icons from Icon Drawer (http://www.icondrawer.com/ http://www.icondrawer.com/). While they look fabulous in their own right, IMHO they do not fit with the rest of the aesthetics set by OSX (look at the Concentrate and CallitADay apps for examples).