Check out the
Links tab at the upper right of the page. It has links to
Publishers and
Vendors that sell paper models.
Seitz Kreuznach GmbH has a bunch of Schreiber-Bogen card models listed on their eBay page.
https://www.ebay.com/sch/Toys-Hobbie...er-bogen&rt=nc
I have purchased a few S-B models from there, which seems to have some country shipping restrictions.
The vendor is based in Germany.
Further searching shows they have an online shop with card models.
https://www.seitz-kreuznach.de/en/models/card-modeling/
Perhaps the shipping is not so restricted from that online shop.