Vintage Art & Illustration:
High quality size and resolution (if possible). From old children's picture books, magazines, ads, by the great masters of the Golden Age of Illustration (circa 1880s - 1920s.)
Children's book illustrators explored nursery rhymes, Shakespeare, fantasy, fairy tales, and mythology, legend, and lore ~ Many fine painters captured similar themes as well.
This blog includes both, and others that fit.