abstract
alarm
alert
attention
badge
blazon
bone
caution
chemical
chemistry
cranium
danger
dangerous
death
design
emblem
gothic
grunge
hazardous
head
horror
human
icon
insignia
isolated
nuclear
nuke
radiation
radioactive
radioactivity
sign
skeleton
skull
stamp
stencil
symbol
tattoo
template
texture
toxic
toxicity
triangle
triangular
tshirt
virus
warn
warning
yellow
zone