Thanks Joe for the link to the German Music Archive.
I hadn't been aware of the organisation before your post.

I have also found that there is a Deutsche Volksliedarchiv / German Folk Song Archive, which has it's base in Freiburg, as part of the university there.

Their catalogue is searchable online.
https://www.zpkm.uni-freiburg.de/collections/germanfolksongarchive

_

Thanks to everybody else re. their posts about collections like 'Des Knaben Wunderhorn' and Erk's 'Deutsche Liederhort'.


All very helpful, and much appreciated!

T.O.