Trapped Troves would introduce small areas on larger islands with notable caves that have a chance to spawn some Kingly loot (2-3 pieces?). The loot is protected by traps and a few strong skeletons, meaning you can either sneak the loot out, or take out the skeletons blazing.
Not a massive feature, but might give a sense of worldbuilding, and an incentive to further explore islands as well as take note of important locations.
