OsmAnd - Global mobile map viewing and navigation for online and offline OSM maps
QGIS - QGIS is a desktop geographic information system, or GIS.
MAPS.ME - Fast, detailed and completely offline maps for mobile devices
GRASS GIS - GRASS GIS is a free Geographic Information System (GIS) software used for geospatial data management and analysis, image processing, graphics/maps production, spatial modeling, and visualization.
Komoot - Plan Your Perfect Hiking, Mountain Biking or Road Biking Adventure
ArcGIS - ArcGIS software is a data analysis, cloud-based mapping platform that allows users to customize maps and see real-time data ranging from logistics support to overall mapping analysis.