One often overlooked but significant risk of downloading ROMs from unofficial sources is the potential for malware. Unlike official storefronts, these sites and file hosts have no quality control.
The Internet Archive (archive.org) is a non-profit digital library that hosts millions of user-uploaded files, including historical software and gaming backups. While it is safer than sketchy, ad-ridden ROM websites, you should still navigate it with caution.
The Internet Archive hosts several significant Wii U collections worth exploring:
Nintendo maintains an aggressive stance against unauthorized distribution of its intellectual property. The company has: