I would like to think my Exo Titan keeps a weathered keychain of a teddybear around for no reason other than he likes to look at it. My Awoken Hunter has a metal shard from the Reef to remind her of "home". Finally my Human Warlock has an worn out ipod on her side at the ready because shes a Guardian of the Galaxy lol. And since I use my Titan and Hunter a lot, my Titan also keeps a Hunter knife, and my Hunter keeps a Titan flash bang grenade. This was really cool to think about :)