I would love to see gold coins as well as the current silver ones. They would similarly have three variants, each worth twice as much as their silver equivalent. I also suggest silver and gold coin blocks, crafted with nine of the most valuable coins. Each coin block would have a slab and stair variant, and obey the laws of gravity. The stair variants would include more 'steps' in each individual block.
Alternatively, nine of the lowest level coins could be used to create a coin layer. These layers would be able to be stacked like snow.
I lastly suggest gold, silver, and bronze goblets, which would funtion like mugs.