PNG ICO ICNS MORE
Ravenna
wrong, Error, warning
Chocolate
256x256
warning, Error, exclamation
Fugue
Alert, Rss, warning
16x16
Direction, Error, warning
Pixelicious
wrong, exclamation, Error
32x32
Office
wrong, Alert, exclamation
UI
Pixel
Fugue Icons
exclamation, feed
Business & finance
Smooth
Pretty Office
Alert, exclamation
exclamation, Direction
feed, exclamation