The Indiana Department of Natural Resources will pay you for seeds from certain trees.
Every year, the DNR’s Division of Forestry does a statewide seed collection to diversify their seed source, and later plant more trees across Indiana.
Some of the species they’re looking for are black walnut, red oak, bur oak and shellbark hickory seeds. Don’t think you’ll become a millionaire though. You’ll be paid a few cents for each seed.