PNG ICO ICNS MORE
Silk Companion 1
read, Alert, reading
DarkKhaki
16x16
Fugue
Error, exclamation, Alert
Function
Alert, wrong, warning
48x48
Radium Neue
Error, warning, Alert
256x256
Signs & symbols
Smooth
Super Mono Basic
Basic, exclamation, frame
UI
Pixel
Fugue Icons
Map, exclamation