Yup, poor Pluto is excluded from the planets series—but the lovable dwarf planet did get it’s own set.
On that note, back in 1991 a 20-cent “Pluto: Not Yet Explored” stamp was released, and it was carried aboard Horizons on its mission. To celebrate their success, NASA team members hoisted a print of the stamp that crossed out the words “not yet”. Clearly, the entire mission was about overcoming the embarrassment of that stamp.
As you will see below, the images used for the stamps are pretty stunning. It almost makes me want to send a letter.
The Views Of Our Planets stamps come in a set of 16 with two stamps of each planet. Pluto Explored comes in a sheet of 4.