Almost 6000 icons from the Amiga MagicWB, in PNG format. These come originally from here, but were converted from the original INFO format to a more usable (at least for UNIX, Windows and the likes) PNG format.
For more info about the icons themselves, credits and so on, have a look at the README.txt file.
MagicWB website: http://www.sasg.com/mwb/
Wikipedia: https://en.wikipedia.org/wiki/MagicWB