Maybe a shot of this ellusive meteor strike that created the Mudokon paw print on Abe's Moon.
But yes, pictures of material that never made it into the games could only expand our understanding of Oddworld, which is something I know we're all fascinated by.
I also specifically wonder if there'll be the Mudokon skeleton in there that seems quite sought after. I have it in a magazine, but it's terribly small.