Most of the Tomcat characters are rigged with Autorig pro. This video shows how to install the free support plugins for these rigs.
The full autorig pro can be found here:
https://blendermarket.com/products/auto-rig-pro
Character in video can be found here:
https://www.cgtrader.com/3d-models/character/woman/california-girl-rigged-character-for-blender-and-vtubing
