Links to online photographic plate archives
DASCH - Digital Access to a Sky Century @ Harvard
APPLAUSE - Archives of Photographic PLates for Astronomical USE
Digital Plate Archives of Hamburg Observatory
Heidelberg Königstuhl Archives
University of Toronto David Dunlap Observatory plate log books - use the search term "David Dunlap Observatory log book"
Yerkes Observatory plate archive - Excel spreadsheets of various plate series
Carnegie Observatories plate archive search tool for Mt. Wilson, Palomar and Las Campanas plates
Ukrainian Database of joint plate archive (DBGPA V2.0)
KODA Kanzelhöhe Online Data Archive