Masters Of The Universe Paintings
Gigantic version available here.
Most of the paintings above were created by William George. More Masters Of The Universe packaging art can be viewed at the Grayskull Museum website. They have a large collection of some bizarre prototype pics and conceptual art here. Scroll through this collection to see some of the more bizarre Masters toys that never made it to the shelf.
This last painting with the Horde was created by Earl Norem, more of his artwork can be viewed here.