Official Batocera releases do not include copyrighted ROMs for legal reasons. However, the retro gaming community shares "ready-to-go" builds through various enthusiasts:
Sites like Arcade Systems or AliExpress sell physical 500GB hard drives that are already flashed and ready to boot. How to Install and Boot Your 500GB Image batocera 500gb download
The Ultimate Guide to Batocera 500GB Downloads: Everything You Need to Know Official Batocera releases do not include copyrighted ROMs