This is a zipped collection of planet and planet-esque objects. There are also a couple of "bonus" ring systems in there. Everything is a PNG file, so dropping these into your own work should be relatively painless.
Because I didn't originally intend to offer these as stock, the file resolutions are all over the map. Also some planets have unshadowed versions, and some don't.
Credit would be greatly appreciated if you find any of these useful as major elements in a piece of work.