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Network & communications
3D
BeOS
beos, warning, Alert
Black
128x128
UI
Smooth
Ultimate Gnome
severe, weather, Alert
256x256
Computer & hardware
Discovery
Alert
32x32
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Desktop apps
Free Applications Icons
Alert, hanger, warning
24x24
warning, ban, Block
Business & finance
Phuzion
warning, Alert
Mixed
Iconza
Pixel
Gnome icons
severe, Alert, weather
Splashyfish
notice, Alert, triangle
16x16
Family & home
Cartoon
Kids
Critical, Attention, Error
Crystal Project
Alert, update, download
Glaze
warning, messagebox, Alert
64x64
DRF
Attention, Alert, exclamation
Crystal Clear
Message, critial, Alert
48x48