One of them is called MapTiler Cloud [0], which is based on our own open-source project OpenMapTiles and data from OpenStreetMap and offers base maps in vectors and rasters.
Apart from it, there is a MapTiler Desktop [1] (and Engine [2]), which is a desktop software producing raster tiles (the support for vector tiles is work-in-progress).
[0] https://www.maptiler.com/cloud/ [1] https://www.maptiler.com/desktop/ *[2] https://www.maptiler.com/engine/
Looks like it's an online map editor/map viewer that supports both vector an raster images.
I also found that if I hold ctrl I can rotate at random and even go "3d" and see some of the building's heights (in London anyway).
I've got no interest or relation in this (apart from being a OSM contributor years ago), but this is one of the most convincing alternatives to google maps I've seen. The free-rotate on the vector tiles really makes a difference.
Could I asked why you stopped contributing? I kind of feel like the userbase is struggling a bit, and I wonder if it's just Google's (using Android's) influence, or if it is something else.
Alas, I couldn't find what this has to do with OSM anywhere, so I don't get why it's mentioned in the submission title.
The software generates map tiles out of OSM data, based on a few sample points I looked at.