List of websites from which you can download gpx or kml files which contains tracks or routes. After downloading these files with your favorite tracks or routes, you can open them in GPX Viewer. To the right of the website link there is their slogans.

https://www.gpsies.com - discover over 5 millions of tracks https://www.alltrails.com - your guide to the outdoors https://www.mapmyride.com/routes - find your path anywhere https://www.mapmyrun.com/routes - take on new challenges https://www.mapmyfitness.com/routes - take on new challenges https://www.tomtom.com/en_gb/adventures - discover the best trails near you https://www.strava.com - the app for runners and cyclists https://www.bikemap.net - find your perfect bike route