I found this East German desktop calculator series with the magnetic stripe paper cards. (5x18.8 cm, see previous thread about Diehl alphatronic).
Diehl alphatronic calculator (1973) magnetic cards part 1
There were 3 models with different memory configurations.
The K1001 had no magnetic card. The K1002 had one, and the K1003 had a magnetic card and a thermo printer.
There were also other robotron computers with (similar) smaller and (larger 20x30 cm cards) like the Daro 1370.
Not sure if they created everything on their own. I only knew HP calculators with smaller cards. The TI SR-60A had similar cards. The write protection is different. (Ripp-off one corner instead of a punch). The first desktop calculator was the HP 9810 (1968).
Here is a smaller replica (with WINCOR Nixdorf keys next to an original (open and closed)
and the project page with downloads