Wikipedia
Nuvola
Nuvola (from Italian " cloud", Nuvola as evolution of the SKY icon theme) is a free software icon set under the GNU LGPL 2.1 license, created by David Vignoni. Originally created for desktop environments like KDE and GNOME, it is also available in packages for Windows and Macintosh. The final version, 1.0, contains almost 600 icons. The default set is in the PNG graphics format; an SVG version is also available.
The application icons, in particular, colourfully represent a wide variety of commonplace and easily recognised objects.