So... probably would have been better to ask in a piracy community/instance. Not sure of the rules in this community.

That said, google NoIntro Archive, or search for NoIntro on archive.org

NoIntro is a group that collects file hashes (unique fingerprints) of known accurate and good rom files for games. There are people out there that use those hash lists to compile rom sets with all the rom files in them.

You can generally find NoIntro rom sets on torrenting sites, but the most reliable and safe source lately has been from people uploading those sets to the Internet Archive (archive.org). You can dig down through the zipped folders and individually direct download what you want, you can direct download the whole set, or you can torrent it from archive.org (this is probably the option you want).

NoIntro primarily covers cartridge games. For disc systems I believe you'd be looking for sets from the Redump group.