PNG SVG PSD EPS MORE
Signs
Flat
Alerts
warning, Signaling, Attention
Tomato
512x512
Construction
warning, Attention, Error
PNG ICO MORE
24x24 Free Application
warning, wrong, Alert
24x24
PNG ICO ICNS MORE
Farm-Fresh Web
Alert, wrong, warning
32x32
Tango
Alert, Dialog, Error
WP Woothemes Ultimate
stop, no, exclamation
256x256
Business & finance
Glyph
48x48 Free Time Icons
Abort, exclamation, Up
48x48
PNG MORE
Desktop apps
3D
Free Applications Icons
Alert, exclamation, General
Shopping & e-commerce
Smooth
Woothemes Ultimate Icon Set
warning, stop
128x128
Signs & symbols
34aL volume 3.2 SE
Message, exclamation, warning