Oddly enough, many boasted advanced design features. This is because most evolved from war torn aircraft factories which were prohibited from building airplanes after the war but still employed some of the finest and most experienced aircraft engineers.
Most microcars sported one or two cylinder motorcycle or motorscooter engines (usually two stroke designs), and often evolved in three wheeled configurations to take full advantage of favorable tax treatment under loopholes originally designed for motorcycle/sidecar rigs.
They were considered "Kabinenrollers" or "enclosed scooters" and were intended to bridge the gap between motorcycles and "real' cars. Now, that's not the whole story. There's lots of micros and minis, some of them built today, some from the turn of the century. Here are some links to sites which will help to explain what this is all about.
Get to know some of the likely attendees…
Try to imagine RIDING in one of these, because you may just at this year's Classic.
More Microcar sources…
The 2019 Microcar and Minicar Classic Homepage