Pulleys & Ascenders
Climbing pulleys are usually used for hauling equipment when doing big wall climbing; to protect the leader from being pulled off the wall when a second falls; or when climbing solo and needing a self belay. You can also use them as training assistance, for example if you want to reduce your weight when doing pull ups.
An ascender is a piece of gear used to directly ascend a rope, or for facilitating protection with a fixed rope when climbing on very steep mountain terrain. In routesetting they come in really handy.