Pricing
free
CloudRig
CloudRig is (reportedly) the main rigging system used in the Blender Studio.
CloudRig used to be an “Extension” for Rigify. However since Blender 4.1 it has become a separate addon. It is still heavily based on Rigify (I think you can call it a Rigify-fork) so if you are familiar with Rigify, CloudRig should be easy to navigate.
One of the main learning resources for the CloudRig System is currently only available with a subscription to the Blender Studio service: