I am trying to find some documented list of types like: bpy.types.VIEW3D_*, bpy.types.3D*, bpy.types.TOPBAR_MT* and other types that relate to parts of the UI, especially those that relate to where I can prepend/append menu items.
In this particular case: a new RMB menu item to add a custom property and paste as a driver. But in general to find out where these are documented or how to obtain a list. If I type bpy.types.[escape] into the console the resulting list is too long.
for t in bpy.types: print(t)