Do you have too many abilities cluttering your action bars? Do you find it difficult to set useful keybindings for all of them? Then OPie may be what you're looking for!
OPie allows you to perform several actions using a single key-bind or mouse button; it enables you to create rings for your less commonly used abilities, items, macros, trade skills, mounts and even raid markers!
It ships with several prebuilt rings, such as: quest items, trinkets, raid markers and class-specific ones. Yet, it allows you to create your own rings and customize them to your liking: rings can be themed, buttons can be colored, or you may even create nested rings!