Searching Google for a "RetroArch BIOS pack archive" will lead you to a minefield of broken links, fake downloads, malware, and potentially legal gray areas.
You load a game. The core loads successfully. But instead of the iconic PlayStation boot-up sound or the Sega CD logo, you get... nothing. A black screen. Or an error stating: "Firmware is missing." retroarch bios pack archive
Now, go play your games. The power of emulation is in your hands. Searching Google for a "RetroArch BIOS pack archive"