The Broken Crank Mechanism and the Discoverable Crank Handle... Because every single RPG game I've ever played isn't complete without it

This discoverable item would just let you interact with the scenery a bit, it would let you lower the platform on Thieves Haven, possibly open a large harbour gate, use canal locks to row rowboats further upstream, raise and lower bridges that may block the way to buried treasure and add to future Tall Tales