PNG ICO ICNS MORE
Farm-Fresh Web
chart, wrong, graph
YellowGreen
32x32
Fugue
warning, exclamation, Alert
16x16
Summer Collection
Alert, wrong, warning
256x256
warning, Error, wrong
Signs & symbols
Smooth
Super Mono Basic
exclamation, green, Basic
48x48
UI
Pixel
Fugue Icons
Block, exclamation