Before diving into sources, it is important to understand what constitutes a "good" ROM. Not all files are created equal.
For those interested in replaying PS3 games, there are legal alternatives: ps3 rom megathread best
Best for: Quality assurance.
The official RPCS3 website hosts a wiki. While they do not host ROMs, they link to the best versions of games. For Red Dead Redemption, they might specify: "USA version BLUS30418 required for optimal performance." The best megathreads tag their files with these serial numbers so you can cross-reference. Before diving into sources, it is important to