alloy
aluminum
background
banner
board
border
brand
bronze
brown
construction
copper
copyspace
crude
dirty
frame
framework
grain
grunge
illustration
industrial
industry
iron
ironworks
layout
line
metal
metallic
old
panel
pattern
piece
plaque
plate
rust
rusted
rusty
shape
sheet
sign
space
square
stainless
steel
template
texture
time
tin
wall