The Metropolitan Museum of Art in New York has made out-of-print museum publications (such as out-of-print catalogs) available on line as downloadable PDFs here, on their "Met Publications" page. The page is set up to permit the interested researcher to search for publications in particular areas of interest.
The Met's Costume Institute primarily features costumes from the 18th century to the present. If you are interested in those eras, the Met Publications page may be of interest to you. I have found several lovely catalogs with full-color photographs of gorgeous 18th and 19th century gowns and a few 18th century men's suits, and there is at least one catalog featuring costumes from the Ching Dynasty. Have fun!