I was at a bookstore the other day and chanced upon a small volume of books called Patterns published by the Victoria & Albert Museum. The volume has four books (they are also sold separately) devoted entirely to patterns and prints from designers who had made their names with creating some of the most beautiful, intricate, colorful, riotous, ad infinitum patterns around. The books also come with CDs so you can print out the patterns.
The patterns below are from 19th century architect Owen Jones. I find it amazing how these patterns still work in this modern age.