So since we have pigs now...why not have truffles?
Commonly dogs were used for truffle-hunting, but pigs were also used, since they would sniff out the fungi and proceed to dig it up. If truffles were added, perhaps if you had a certain leash equipped along with a pig, you could search for truffles. The system could be similar to the way you find wells, or just requiring a high exploration / perc combo while having the pig leashed. Since the truffles are symbiotic fungi, they would only spawn in the light forest(?) areas (the one with birches, willows, mulberries, etc.). Once harvested the truffles could be put on a herbalist table to dry, or used directly in certain cooking recipes.
I would have a more fleshed-out idea, but sadly it is midnight. Any comments / additions would be appreciated.