Either the complete hubs or just the axle, cones, locknuts and qr skewer can be used as a "travel axles" to protect the dropouts of the bike frame and fork when the wheels are removed. I use these when packing an S&S coupled bike in it's case or when a bike is carried in the back or trunk of a car and the wheels have to be removed to make it fit.

Use the rear hub with a worn out cassette or freewheel to hold the chain for cleaning or other bike repairs while the rear wheel is removed. That keeps the chain from scratching the stays and keeps cleaning solvent out of the bearings and off the rim of your wheel.

Bend a section of a 6" piece of a spoke into a shallow U-shape and then bend the ends inward to make a chain holding tool that keeps the chain ends in place while you insert the joining pin or master link