Relics - A

Angel Feathers = If recovered, the physical feather of a manifested Celestial would grant a Conquistador a small measure of protection against Infernalism as well the power to call out to that Celestial for help (making the Conquistador a temporary Angelus).
Antikythera Device = Could this be an ancient, primitive computer?
Apple of Eden = An Apple of Eden would grant its holder the greater powers of precognition. 
Ark of the Covenant = The ancient Ark has been the source of no small amount of conjecture and myth-making. For more info on the Ark see this Link here.