Use the links below to start your research. Each contains examples of ephemera from the former East Germany. Once you discover brands, bands, and other specifics, conduct a specfic search for those items.
New York Times - Great introductory article detailing what "Ostalgie" means.
Ostalgie and the Politics of the Future in Eastern Germany: Scholarly analysis of the impact of the phenomenon of Ostalgie. Provides examples of film, TV, etc. for reference.
Pilot Guides: Short, list-based overview of Ostalgie
Germany Info: Additional references to examples
Deutsche Welle: Collection of articles