BlenderOni
BlenderOni is a Blender add-on intended as an integral companion tool for the Animation rig for Blender. It contains functionalities that automate a lot of operations necessary for the rig to function and be used properly. However, the vast majority of the add-on's options can also be used for general Blender tasks.
BlenderOni can be downloaded HERE.
History
When the Rigify-Oni rig was first released to the public, it was meant to be used together with a number of scripts stored within the Blender scene containing the rig. However, those scripts were not ideal - they were awkward to use as setting up the appropriate values was possible only by changing the script code.
Those scripts have become obsolete with the introduction of BlenderOni, which is essentially little more than those scripts wrapped into a GUI. The scripts are nonetheless archived HERE for legacy purposes.
Options
To be further described
Bake Keyframe Rotation Mode
Change Rotation Mode
Adjust Throw Target
Object Constraint Switch
Bone Constraint Switch
Object Visual Transformer
Bone Visual Transformer
Set Object Constraint Targets
Set Rig Bone Constraint Targets
Constrain Character Model
Use cases
To be further described, but probably best to link to the rig documentation