I love Bookplate illustration, also called Ex Libris: Basically a design or illustration on a card, placed in a book, that declares ownership. Ex Libris Effectively means "From the library of", followed by the name of the owner.
I made a small series of Bookplates based on fictional families of books that I love. This was my most successful attempt. Ex Libris Stark, from Game of Thrones. The Latin phrase, "Venturaque Hiemis", roughly translates to "Winter is coming."