@ben @davedelong or CoMaps forked from Organic Maps, because of reasons detailed here:
https://openletter.earth/open-letter-to-organic-maps-shareholders-a0bf770c
I also recommend the app named Every Door to participate in adding/editing the OpenStreetMap data, which benefits every one.
@davedelong CoMaps or Organic Maps ?
They don't offer as many features, but they are still quite good. And no ads.

Popular map portal covering whole world by wide range of maps - basic, outdoor (hiking/cycling), traffic, winter. It offers possibility of aerial and 3D view. Extensive amount of travel points of interest. Users are able to search places, plan routes, measure ground and create and share own content. Tourists worldwide use map portal for detailed hiking and cycling maps and extensive tourist guides.