Legout and Decibel. The four dinosaur cassettes. Simply because their molds cannot be reissued, are very rare/expensive and they were pretty crappy anyway. Doesn't matter that there is no Masterpiece Blaster, they still work with the original Blaster. Nor should it matter that they weren't on the cartoon. Doing them as Masterpiece toys would be pretty awesome. Plus it would be good if they were repainted into Decepticons.