While adding magpies (tasty birds with a tendancy to steal colorful objects away) would be interesting, I wanted to share this observation; people like to collect things. They will do this, and enjoy it, even when there is no in-game benefit. In fact, having a use for these items would partially detract from the pure joy of collecting things.
Imagine that one could use clay, herbs and minerals, and, with the help of skill, dexterity, Psi, luck, and the phases of the moon, produce a unique figurine with no particular utility. Maybe they could be displayed on a shelf or a case for appearance's sake.
Perhaps having a complete collection provides some small bonus.
This wouldn't be a diversion for high-level players alone, though. I imagine that chess pieces and other knickknacks could be made using similar sets of rules, but without high-level requirements.