In the example, those aren't ALL the icons, and there only 2D. And you don't have to use these on Rocketdock. Oh, no, you can use them ANYWHERE!!:D
Most of them are a dingbat font, but the Microsoft office ones (except Outlook) are actual letters. ;)
Some of them don't look good as I had to select and resize it and when you do that on MS Paint, it doesn't look good at all. :(