Epic historical items and relics from the war that can be collected, which have a story and video of where they are originated or how they got lost. Like dreams from the past.
Special experimental 10x scope. Costume pieces or decals. Smoking Pipe. Tophat. Ornaments. Monocle. Preserved diary of a crazy king. Watchmakers stainless pocket watch. A golden spoon. High octane moonshine. Dense darkbrown tar. Phoenix alpha claw. etc..
Account bound and can't be traded or sold but collected without taking space as special easter eggs that are hard to find in locations that are alright to scavenge in.
Cinematical flashbacks explaining where the item originated from. Pre-war, during war or post war. Funny story, Romantic, Heroic, Disasterous, Scientific or Legendary.