You are specifically describing street maps. There are other sorts of maps, even maps for areas with named streets where the streets are not named on the map.
A local orientation organization has checkpoints around many areas here in Sweden. You visit each one and tally up how many places you've visited. The web site lets you enter the 1- or 2-digit code for each checkpoint if you want to track it that way.
Here's my local map: https://koncept.orientering.se/provapaaktiviteter/hittaut/tr...
There are no street names on those streets. There are contour lines, making it a topographic map.
Look at https://en.wikipedia.org/wiki/Topographic_map and you'll see other examples of topographic maps showing streets but not listing all or even most of the street names.
In your locality. Not all places have street names.