CDRI: Digital resources for the study of religion - The Cooperative Digital Resources Initiative of the American Theological Library Association and Association of Theological Schools - part of the ATLA Digital Library is a repository of digital resources contributed by member libraries. Includes manuscripts, postcards, woodcuts, coins, maps etc.
Digital Scriptorium -" image database of medieval and renaissance manuscripts that unites scattered resources from many institutions into an international tool for teaching and scholarly research"
Hill Monastic Manuscript Library - "resources for the study of manuscripts and currently features manuscript cultures from Europe, Africa, the Middle East, South Asia, and Southeast Asia. The site houses high-resolution images of manuscripts, many of them digitized"
HOLLIS Images - Harvard Library's catalog of images from the various collections of Harvard University - can limit to public domain items only
New York Public Library Digital Library - over 700,000 items including images of prints, illuminated manuscripts, photographs, maps, moving images, sound recordings books , postcards etc.
SOAS Digital Collections - photographs, maps, films, audio, manuscripts and other resources from the collection of SOAS (School of Oriental and Africa Studies) , University of London