OsmAnd - Global mobile map viewing and navigation for online and offline OSM maps
GPX Editor - Load, modify and save your GPX 1.1 files.
MAPS.ME - Fast, detailed and completely offline maps for mobile devices
gpx.studio - View, create, edit and combine GPX files online to correct your activity data or design new awesome routes.
HERE WeGo - HERE WeGo - Maps - Routes - Directions - All ways from A to B in one
GPSies - With GPSies you can view and download tracks which have been recorded by a GPS device.