Fatmap. It was freemium, but now it’s moving into Strava, who knows how much of it they’ll hide behind subscriptions.
There’s so many great FOSS maps, but I haven’t seen any that give you the 3D view that Fatmap does. It’s essentially Google Earth with overlays of routes for various activities.
Mass produced to be as cheap as possible, vs carefully built and engineered to last as long as possible.