PNG ICO ICNS MORE
UI
Pixel
Fugue Icons
exclamation, Hourglass
SteelBlue
16x16
exclamation, Jar
water, exclamation
globe, exclamation
Mixed
Led Icons
exclamation
Network & communications
Smooth
Oxygen
exclamation, Alert, Information
128x128
Book, exclamation
Books, exclamation
exclamation, Layers