The most obvious example is pathfinding. (The activity from which the discipline takes its name in the first place.)
As an example, finding the shortest route through a road network (like Google Maps does), or automatically scheduling a multiple-leg trip in a public transit network (like many sites for the networks of different cities do).
It could also be used to predict resource acquisition patterns in growing fungi, migrations of animals, or designing traffic networks in the first place.
It could probably even be used to evaluate options in complex processes, although by the time you have the map you need to search for the best path, you will probably have solved your initial problem to begin with.
The essential truth one needs to remember being: Most everything can be looked on as a game, so most every game development technique can be used outside of what we normally call "games".