i actually had an idea related to this: In dungeons, a LOT of crafting mats drop. Toto-rak has diremite things dropping like rain (useful for making velveteen), Brayflox HM has a lot of raptorskin, etc.
My idea is the ability to opt out of future drops you've already acquired using a list. That way, if something drops you don't want cluttering your inventory, someone else in the party who wants it will receive instead.
This ALSO allows for another fun little thing: item checklists for the completionists!