PNG ICO ICNS MORE
Desktop apps
Smooth
Farm-fresh
Toxic, danger
DarkGray
32x32
Signs & symbols
32px Rounded icons
Radioactive, danger
DarkSlateGray
UI
Ultimate Gnome
danger, Emblem, Toxic
Indigo
256x256
Shopping & e-commerce
Woothemes Ultimate Icon Set
danger, Biohazard, nuclear
Black
128x128