Historical information undated
Various unions, stamps and ephemera 1890-1940
Industrial Workers of the World, stamps and ephemera circa 1905-1940
Stamps and ephemera from strikes, boycotts, and fundraisers circa 1914-1940
International Labor Defense, stamps and ephemera circa 1925-1940
International Workers Order and other socialist groups, stamps and ephemera circa 1930s
Continental Congress for Economic Reconstruction, stamps and ephemera 1933