East Berlin relied more on trams and S-Bahn and the U5 which was mostly built higher than ground is the sole line extended by east Berlin. The only real underground U-Bahn station developed by east Germany is "Tierpark" together U5. You will discover naturally other stations, developed by other architects; https://travisrwbfj.wikibriefing.com/2864333/about_mobile_cocktailbar_berlin