Armor (biological) – The armor is alive and/or composed of organic matter.
Venom (Marvel) has armor that is alive but can corrupt the user.
X-O Manowar (Valiant) has an armor that looks like a machine on the outside but is clearly biologically based on the inside (X-O Manowar Database #1).
In 4001 AD: X-O Manowar, the X-O Manowar biological armor has been grown into a much larger armor.
Cannonbolt (Ben 10) is an alien with natural armor.
Asheiran Armor is made up of micro crustaceans (Dragon Magazine Annual 1).
Rabak Armor is made of wood (Dragon Magazine Annual 1).
Sindar Web Armor is made of spider webs (Dragon Magazine Annual 1).
Sul Armor is made out of living insects (Dragon Magazine Annual 1).
Taboo (Wildstorm) has an organically based armor (WildCATs Adventures Sourcebook).
Next 045) Armor (dermal)