how to access a rigify armature selector UI? I generated a rig using rigify but I can't seem to find a UI to select the armature i want. I know other VFX setups usually have a 'paper doll' like image with buttons for each part of the character available to animate. Does rigify provide this UI?
There is no such feature as far as I know.
Rigify give you a menu that helps hide/unhide parts of your rig. Look in the N-panel (press "n"). In Item you should see Rig Layers.