Monica and Cliff Robinson have created an invaluable site containing
details of over 1,000 stained glass windows in Buckinghamshire. The site
includes about 2,000 photographs.
Institut Royal du Patrimoine Artistique/Koninklijk
Instituut voor het Kunstpatrimonium (Royal Institute for the Study and
Conservation of Belgium's Artistic Heritage)
Stained glass is represented among the several hundred thousand
items.
The Michigan Stained Glass Census is run by the Michigan State University
Museum. It includes an impressive photo archive as well as information about
American stained glass artists.
The sixteenth-century windows in St John’s Church (the Sint Janskerk) in
Gouda are the finest extant examples of early glass in the Netherlands. Two
websites provide excellent guides to the church and its famous
glass.
The Metcalf Collection of pre-Second World War photographs of European
stained glass windows (mainly French), hosted by The Index of Christian Art,
Princeton, USA.