Around the map, either after the player completes a certain house or during free roam mode there should be spots you can dig with the shovel scattered around. Digging them could give you useful items if future patches add more sandbox/scarce items, or they could give you lore items like the tapes (I don't know the lore so don't ask for an example)
They could be randomly distributed or in set spots, and maybe there could be a treasure map you can find somewhere with their locations?