Kurt Aumueller from the MFGCast has a fun little RPG Hack based on the Core System called Welcome to the WWA! It’s about woodland creatures wrestling for fame, action, and glory! Check it out for free on DriveThruRPG and Itch.io:
DriveThruRPG: https://www.drivethrurpg.com/product/333538/Welcome-to-the-WWA
Itch.io: https://mfgcast-entertainment.itch.io/welcome-to-the-wwa