94 - Plutonium | Natural forms, Nature, Oxidation state
Plutonium-244 doesn't naturally occur on Earth not because it's too unstable, but because the supernova(s) that seeded our solar system was only powerful enough to produce Uranium-238. There are probably other worlds
Plutonium - Wikipedia
Thursday/ Iran's plutonium – Willem's Planet
Plutonium-239 - Wikipedia
Uranium: Facts about the radioactive element that powers nuclear reactors and bombs | Live Science