This searches some of the larger collections of German texts on the Web:
Shannon Reference Z2231.W74 1992
Shannon Reference Z2231.G7 Use the Index (Ref Z2231.G74) and Hansel's Literaturrecherche für Germanisten (Ref Z2235.A2H24 2003) to find things in the various editions.
Shannon Reference PT167.B75 1986 Brief biographies, often with picture, and bibliographies of primary and secondary works.
Shannon Reference Z2230.K7 Inhalt = List of included authors. Looseleaf format with occasional updates. Lists not only books, but also their magazine and newspaper articles.
Shannon Z1014.V47 1883. Use the list of microform collections of early printed books to find titles not listed in VIRGO.
Shannon Z2222.W64 1972. Use the list of microform collections of early printed books to find titles not listed in VIRGO.
List of books published in the German-speaking countries. 1700-1910 - Shannon Reference Z2221.G46. 1911-1965 - Shannon Microform Room microfiche 1399
Shannon Reference Z2231.D4 1965
Shannon Reference PT1188.D8