Shakespeare, the complete works. Maintained by the Classic Literature Library, UK. Excellent resources. The latter has on-line editions of the King James Bible, Sherlock Holmes,Charles Dickens and Charles Darwin, Bram Stoker and several others.
Mr. William Shakespeare "A complete annotated guide to the scholarly Shakespeare resources available on the Internet." A very fine resource.
The Victorian & Edwardian Theatre Collection's Theatre History Resources at the Templeman Library, University of Kent at Canterbury, and the Theatre History Collection. Excellent links to 17th, 18th and 19th century resources, with a special section on the Savoy Operas.