A Shinkalion Z sticker book by Shogakukan Televi-Kun that is supposed to be released in September 2021 depicts what appears to be a combination of Shinkalion Z E5 Hayabusa and a Doctor Yellow on its cover, with a slogan saying "Completed! The strongest Shinkalion Z!!"
The official name for this new Doctor Yellow unit and this combination are still unknown. Could this be the "Super-Z Combination" that has been rumored?
Note: Before more official information regarding it is revealed, DO NOT create any wiki articles for it.
(Pic in the comment)