Merkur
A world-famous Czech kit that has been sold since the mid-twenties of the 20th century. Various models, road and rail vehicles, cranes and many other structures can be assembled from it.
The original parts are made of metal, but it also contains thinned plastic parts.
I thought of making them using 3D printing. You will achieve cheaper production and a larger range of colors.
Good luck with 3d printing and merkur.

I will gradually add more parts.