When you are drinking beer in Germany, one of the pleasures of the experience is the decorative glasses, which contain the brewery's name, logo, and in many cases, the name of the city or town. I have been collecting German beer glasses ever since I was in the Army in Germany in the 1960s. Most of them I purchased from the gasthaus or restaurant where I was dining and brought back to the US. Some I have purchased at German places in California like the Alpine Village in Torrance or Old World Village in Huntington Beach.
Most German beer glasses bear the name "Rastal", the company (pictured below) which produces them. It is the largest such company in Germany. They are located in the town of Hoehr-Grunzhausen, near Moenchen-Gladbach. They also make glasses for other European breweries.
You may also have encountered many glasses bearing the mark of "Sahm". It seems that the companies are intertwined since Rastal was founded in by Eugen Sahm in 1919 and the ownership is still with the family. I understand the factory is open to visitors and glassware can be purchased there.
At the risk of being repetitive, here are a few samples.
Franziskaner (Munich) Spaten (Munich) Kitzmann (Erlangen)
If you happen to be in the area of the factory, you might stop in for a tour and buy some glasses. Of course, you don't need to go to purchase them. Most any gasthaus in the country will be happy to sell you one as a souvenir for about 5 Euros. I have never been turned down. Sometimes, they may give it to you for free.