A big Thank you to pixalism, ZonSoft, speedtwin69 and WalterMo for the nice girls.
Not a Thank you to some other creators they have nice girls too but use a license that forbid remixes. (I made more than five but put them into the trash after reading the licenses. I should read the licenses first.)
The bookends are designed to be printed in this size. (The thin plate on the back is currently 0.4mm!) If you downscale it will make trouble. Need a smaller one? Design by yourself ;)
All were designed fast so they are really not perfect but they look nice and should work. I did not print and did not test they yet. It's your part. If you made one, please post your make.
Need the other side? Just mirror in your slicer.
I guess the most will need support. (Only?) one of the models was hollow, so best set an option to close all holes in your slicer settings before printing. Try it out.