In plowing through my pile of private postal stationery, I found quite a few cards commemorating German stamp shows. Here's a neat set from the Rhine Stamp Exhibition
in Düsseldorf, 20-22 June 1936.
Joyous reception of visitors to the Stamp Show in Düsseldorf
The train emerging from a stamp is based on the design of Mi 583 from the 1935 German Railways
The Patroness of Spanish Specialists arrives at the Exhibition
The joy of stamp collectors, the horrors of Civil Service
Warm greetings from the Airmail Stamp Exhibition
An oddly non-philatelic commemorative cancel was available at the event.