Common Illustrator to Find
Common vintage books I find over and over are the puppet books and the 3d Golden books by the two Japanese illustrators Izawa and Hijikata.
Here’s a link to the completed auctions. You will see that many of them are the 3D hologram type plates on the covers. Those you want to mention have the plates. Be careful since they fall off frequently. They’re easily glued back on to the cover. You’ll find the Mermaid and a few others are top dollar makers.