Today I came across My Home Library a website dedicated to bookplates, particularly to bookplates done for children’s books by illustrators. For example, this one by Martin Brown. If you go to the site you can download it for free as long as you use it only for your own, non-commercial purposes. There are hundreds of them at My Home Library.
I love bookplates, but I never put them in books; I never write anything in a book, either. But I do have a small collection of bookplates, and I love the ones on this website.