abstract
abstraction
ac
background
badge
black
caution
character
closeup
corrosion
danger
detailed
dirty
electricity
erosion
grunge
grungy
hand
high
high stress
industrial
iron
lightning
macro
manufacturing
material
metal
metallic
old
oxidation
production
risk
rough
rust
rusty
sign
steel
stress
texture
the surface has been damaged
uneven
vintage
warning
weathered