This page describe great games that motivated me to walk/cycle more.
Ingress (old one)
Coop, pvp, trans-continental collaboration, user generated content.
Color Planet Resources
Great coop with local friends, motivate to go further away, too much grind in the end game.
Resources
Some pvp, grind required, requires lot of time at the beginning.
Off Grid
Single player, build district sized base (or bigger), lot of revisiting same places.
Magic streets
Mostly single player, become repetitive quite fast.
Run Empire
Single player, after few months lack of content, motivate to go further away.
Domination Earth
Mostly single player.
Primitive Village
Single player, base building, not tied to single location.
Expand
Team based PvP, very long waiting times, could be fun if walking together in group of 3-4 people.