I was curious what they're currently sponsoring; here's another neat OSM project: https://osm2world.org/demo/?lat=52.5239396&lon=13.4104859&ra...

The current demo doesn't seem to cover many places worldwide, but what is there is really neat! To me this already looks better than modern city sim games, because they never seem to get the scale right, among other things.

Not sure what's stopping them from covering more places, since the idea presumably is to generate these tiles from existing OSM data. And in fact one of the easiest things to do with StreetComplete is add the height and type of a building.