This set of seven type specimen sample brochures, released by the Schriftguss A-G foundry in Dresden in the late 1930s, are not only great examples of modernist design, but a nice record of foundry types being created in East Germany at that time. Many of these fonts such as Helion, Diamant, and Duplex appear just as modern today as when they were released in 1937. The entire lot of these 4-page specimen brochures are available here.
Luc Devroye's extensive informational archive of typography lists a number of the type designers associated with the Schriftguss foundry, and select pages from specimen catalogs. Also included is the original Schriftguss A-G logo.