Would absolutely love to see items being used for buying different things, like irons from the mountains to get robots.
also having the ability to find certain items in specific areas, for example the hell bucket could be found in the volcano or items can be made through certain constructions, like farms to get carrots.
maybe have an unlock system with certain items, once unlocked it can be bought in the shop. for example the prismatic apple can be found somewhere deep in the forest