While Jujutsu Infinite is the biggest, your search for exclusive codes might lead you to these other popular Roblox JJK experiences:
While specific "exclusive codes" are not publicly listed in a central repository, they are typically distributed through the developer's community channels or used within specific story modules, such as Juuj Town: Muriel Story Core Gameplay Features Sandbox Exploration
Special rewards reserved for verified monthly project supporters. How to Unlock and Redeem Exclusive Codes