The tiny size of Märklin mini-club all but guaranteed that these tiny trains would also be used for commercial promotion and for collectors. Even a modestly large mini-club collection would not occupy much space. Inevitably, a market emerged for special imprinted cars, items which were produced in very small production runs. Collectors, both model railroaders and numerous others, snapped these specials up.
There is a guide for such cars, Koll’s Spezial Katalog [Verlag Jochim Koll, Bad Homberg, Germany]. The copy that I have is dated 1996, and it shows well over 20 categories, with thousands of cars and a few locomotives that have been specially imprinted. Subsequent editions have been produced, and the numbers are higher for the special imprints.
If you are interested in collecting these cars, it is an interesting pastime. This section of the web site shows just a few of these cars: