The icy bodies in the Kuiper Belt are called "Kuiper Belt Objects" (I know, creative), or KBOs for short. Pluto is the best-known KBO, and one of the reasons it was demoted from being a planet was that thousands of other KBOs have been discovered orbiting in the same region. Only Pluto and one other KBO, Arrokoth, have ever had close-up pictures taken by a space probe. Pluto was visited by the New Horizons probe in 2015, and Arrokoth in 2019. Pluto is very round, made of water ice mountains and nitrogen ice glaciers, and has 5 moons. Arrokoth is only 18 miles (30 km) across, very red, and shaped like a snowman. All other KBOs have only been studied using telescopes, and even the best telescopes on Earth and in orbit still see them as dots, so we don't know as much about their shapes and colors as Pluto and Arrokoth.