Looking for more information on these from SCF members. They are not listed in Scott or Michel from what I can see (although admittedly my Michel is old and my German not great).

The only reference I have so far based on an image search is to this German auction site, where 5 of the 50pf values are are listed as 1921 "arbeiter" (worker) essays for 70 Euros. I only have 4 of the colours (missing the green), but have them in 3 values - 50pf, 60pf and 75pf. Date makes sense given the style of these.
https://www.philasearch.com/de/i_94...64&row_nr=18Mine are on thickish paper, and all have 2 1/2 in pencil on the back - I'm guessing the purchase price grandfather paid back in the day. Any info or pointers to where to look further would be much appreciated.