This AddOn for Vanilla WoW (v.1.12.1) adds an additional circular action bar that normally remains hidden but can be summoned by a click of a (mouse) button.
The RingMenu is hence ideal for storing away action buttons that are frequently used yet need not be present on the screen at all times (e.g. trade skills, tracking spells, hearthstone, etc.).
Before first use, you need to set up a button to summon / dismiss the RingMenu anywhere on the screen. Go to
Main Menu > Key Bindings > RingMenu > Open / Close RingMenu
and choose an appropriate button. This can be any keyboard or mouse button.
Open the RingMenu by clicking the summon button anywhere on the screen. You can now drag and drop actions to the slots of the RingMenu like for a regular action bar.
Open the settings window by typing /ringmenu.
Using the First Button Slot and Number of Buttons settings, you can adjust the range of action button slots that are used for the RingMenu. Depending on your class, some button slot ranges might be already in use for shapeshift forms. Use this list to pick an appropriate range.
Further configuration options include the radius and angle of the RingMenu as well as the color of the transparent backdrop.
You can use the cyCircled AddOn to modify the appearance of RingMenu buttons (see the installation instructions).