Loki is a simple add-on that can save and recall any object X, Y, Z location into a list.
As simple as it gets, Loki could be very helpful in the following scenarios
Need to do a lot of precise object placement in 3D space, save and recall them at anytime.
Swap any object location to any object location on the list.
Save and recall multiple cameras specific position.
Save and recall multiple lighting position.
Save and recall specific position when keyframing animation.
Available from BlenderMarket