A stamp set featuring all of the eight planets in our solar system and the sun! They can be a great way to celebrate space exploration and the beauty of our universe, like countries having short forms for each planet in the top right corner of the stamp would add a unique touch to the set and make it even more engaging for collectors. It is not necessary to have two letters like the countries, it could have only one letter. Such a stamp set would not only be visually stunning but also educational.