what type of metals am i looking for in vehicles

hey anyone seen something that tells me what types of metal are inside of

seatbelt buckles
seatbelt detractors
clocksprings
steering wheel
air bag
air bag sensors
and the air bag computer thing



Im getting all of those from my job but I don't want to miss any special type of metal.
the only metal I'm seeing are cast aluminum, gold, copper, aluminum, zinc, and I think brass.
I have pictures if you think it will help out future noobs. want me to show pictures?