Hi guys, we've recently finished making an app that is now live, we've launched on Monday, still doing some testing, but it's up and running now, though still beta. It's called Blattarco, an educational app, you can send your music to get feedback and support from professional musicians, teachers, and artists; we have a digital marketplace, additional educational materials for subscribed users, and a lot of other... Source: over 3 years ago

I highly suggest checking out Natural Atlas (https://naturalatlas.com/) by the same small team who made the CoTrex app (https://trails.colorado.gov/) for Colorado Parks and Wildflife. A really fantastic team building some absolutely gorgeous topographic basemaps from publicly available data. Hopefully they'll find time to add a slope angle overlay at some point. - Source: Hacker News / over 1 year ago

I highly suggest Natural Atlas. The cartography is impeccable and they’ve been adding features over the last year. Source: almost 2 years ago

Try a recreational-themed map like naturalatlas.com. They will list most all known trails. Source: over 3 years ago