When I used to play runescape, there were small chances of getting caskets when fishing which would have some loot in them.
Could we possibly have some sort of loot crates when doing random actions? For example, when digging we might find a small chest with some random items in it (value depending on how often these crates will show up). When fishing, we might get some sort of crate with loot inside, also with value depending on how rare this event occurs. I think it would be fun to have little incentives to do random "treasure hunting", and I always enjoy finding things like this.