I've got digital and physical copies of 250 designs by Jack Kirby done for Hanna Barbera shows in the late 70s. I bought them from Dave Karlen, who bought them from an animator who worked with Kirby and Hanna Barbera.
Some of them are from the Super Friends show and have Batman and Superman, most are from other 70s shows like Space Ghost, Teen Force, Space Stars and even Scooby Doo and the Lord of the Rings animated movie.
The designs get pretty crazy, and if the reason Kirby left Marvel was over Kirby wanting to be more creative, this is Kirby unleashed.
A few of these pages can be found on the internet in various places, but 80% of the pages I've got haven't been seen by the public. They haven't been published in a book, either, to my knowledge.
Since I'm in Australia and postage for 250 pages would be expensive (like it was the other way around), I can sell a link to a downloadable zip file containing the 250 1-2 MB photos for PayPal funds. We can discuss the price.
Alternatively, if multiple people want to split a price I can post a link here for everyone.
If you're interested send me a PM and we can work something out.