Zombies, Run! (2012)

For anyone who gets bored before they get tired. Every run becomes a mission in an audio drama set after a zombie outbreak, with the story playing between tracks from your own playlists, so the motivation is wanting to hear what happens next rather than chasing a pace. There are more than 500 missions across 11 seasons, enough to cover years of easy runs. You can try it free, and a paid membership unlocks every mission; the App Store lists several membership options, so compare them before choosing. It works at any speed and on a treadmill, a trail walk or in a wheelchair, which makes it a kind pick for recovery weeks when the point is time on your feet, not speed.