Deutsche Schlager from the 30's and 40's
Comedian Harmonists as an example. Formed in 1927 as a unique vocal ensemble and, after worldwide success, had to stop working in the original lineup after they were banned in Germany in 1934. The jewish members went to the USA and reformed with new members, the non-jewish did the same under the name 'Meistersextett'.
Some of the songs here were clearly propaganda and perseverence slogans, for example 'Ich weiss es wird einmal ein Wunder geschehen' (I know a miracle will happen) by Zarah Leander. But there also many nice love songs, novelty numbers, enjoy!