Download OpenEmu-Experimental; download BIOS package; unarchive bios package; duplicate `SCPH5552.BIN` and rename it to `SCPH5501.BIN` open Finder and press CMD + SHIFT + G; fill in with /Library/Application Support/OpenEmu and hit Enter; open the BIOS folder, if it's not, create it.; copy SCPH5500.BIN, SCPH5501.BIN, SCPH5502.BIN from the BIOS package folder you downloaded earlier.
No files in this folder. Sign in to add files to this folder.

Updated 4/21/20

I've written in the past about emulation and OpenEmu, a multi-console emulator front end that uses multiple emulation cores to provide a unified experience to macOS (OS X) emulation.

OpenEmu also sports MAME Arcade emulation support, but its a bit tucked away.

Step 1: Download OpenEmu Experimental

File Name: OpenEmu2.0.6.1.zip File Size: 41.48 MB System: Multiple Systems Version: 2.0.6.1 Downloads: 619,887 Requires OS X 10.11 or higher. An all-in-one emulator.

Go to openemu.org and click the swatch and download OpenEmu Experimental, and install it.

This scfeenshot of the OpenEMU site is old. The design on the OpenEMU website has slightly modified to make the experimental version easier to find

Step 2: Install the MAME core

Once installed, launch OpenEmu, open preferences, and select cores. Click the install button next to MAME.

Step 3: Install games

Games can be nabbed from the usual suspects like ~~emuparadise~~ (defunct), the legality of this is fairly grey. OpenEmu only supports zipped ROMs, so if the ROM comes in a .gz or .rar, be sure to decompress its contents and rezip it. Name it the exact name as before (but with the new extension of zip). OpenEmu's MAME core is version 0.149.1, so its significantly behind the windows version (from 2013 to be exact). Some sites will list the earliest known support needed for the rom in question.

Notably, you'll want access to the dipswitches, hitting F2 repeatedly while the game is launching will take you to most ROM bios screens that enable modes like free play. Note, I had issues resuming games and had to force quit MAME resuming so you may want to hold off resuming games.

Optional: NeoGeo Emulation

Emulating NeoGeo games requires one extra step, you'll need to get the NeoGeo ROM, the one I used is from emuparadise which is now defunct, try a popular search engine and search 'Neo Geo BIOS'. Drag the Neo Geo zip into OpenEmu. You'll see the NeoGeo ROM in your game list, but ignore it and double-click the games as you normally would.

Good luck with OpenEmu. I suggest checking out the Dolphin Emulator as it has a great macOS port for GameCube and Wii, and PCSX2 for Windows for Playstation 2 emulation. Both are able to play old games in HD and UHD depending on your CPU/GPU.

Other recommendations from this blog:

Running up MAME Arcade emulation with MAME/MESS - How to set up the most current version of MAME on MacOS. OpenEMU's MAME core is 7+ years old, and there are quite a bit of newer arcade games supported in more recent versions.
Installing Provenance on iOS 11 with a Jailbreak - Provenance is an iOS multi-console emulator based off of OpenEMU, supporting consoles from the 8 bit and 16-bit eras. The step process hasn't changed for iOS 13.

Updates: 4/21/20 - copy editing, note about layout change on OpenEMU's website, striking out emuparadise as its now defunct.

2Nintendo
3Sony
4Sega
5Atari
6Microsoft
7Other consoles
8Personal computers

Multi-system

File type(s)	Emulator(s)	Backup
BIOS files	RetroArch	✓
BIOS files	Mednafen(standalone)	✓
BIOS files	OpenEmu	✓
ROMs Pack(0.151)	MESS	✓
ROMs Pack(v16) ROMs Pack(v17)	PCem	✓
ROMs Pack	86Box	✓

Nintendo

NES / Famicom

File type(s)	Emulator(s)	Backup	Note
Family Computer Disk System BIOS file	Various	✓	Required for FDS emulation. MD5 Hashes

SNES / Super Famicom

File type(s)	Emulator(s)	Backup	Note
Satellaview BS-X ROMs	higan(bsnes) Snes9x	✓	Required for some Satellaview releases. Including Japanese original ROM, no-DRM ROM and English-patched ROMs (DRM or no-DRM).
Sufami Turbo BIOS file	higan(bsnes) Snes9x	✓	Required for Bandai's Sufami Turbo emulation.
SuperDisc BIOS file	No$SNS(1.6)	✓	Required for Sony's SNES-CD emulation.
Super Game Boy boot ROM	higan(bsnes)	✓	Required for Super Game Boy emulation. MD5 Hashes
Coprocessor firmwares	higan(bsnes)	✓	Including CX4, DSP1/1A, DSP1B, DSP2, DSP3, DSP4, ST010, ST011 and ST018. More information

Nintendo 64

File type(s)	Emulator(s)	Backup	Note
LLE RSP plugin	Project64	N/A
64DD IPL and PIF ROM (JPN Retail)	CEN64	✓	Required for 64DD emulation in CEN64. Japanese region only.
64DD IPL (JPN Retail)	Project64	✓	Required for 64DD emulation in Project64.
64DD IPL (US Retail)
64DD IPL (JPN Development)

Download Bios For Open Emu Vpn

GameCube / Wii

File type(s)	Emulator(s)	Backup	Note
GameCube IPL BIOS file	Dolphin	✓	Optional. Required for rendering original system fonts. MD5 Hashes
DSP-LLE plugin		✓	Optional. Needed for more accurate low-level emulation (LLE) of DSP audio. Required in Dolphin for connectivity with GBA units. An incomplete HLE solution removing this requirement exists.
Swiss		N/A	Optional. GameCube homebrew utility. More information Old version (r241)
Wii WC24 network SSL certificates		✓	Optional. Required for connecting to Wi-Fi Connection service. More information

Game Boy / Game Boy Color

File type(s)	Emulator(s)	Backup	Note
Game Boy (DMG) boot ROMs	Various	✓	Optional.
Game Boy Pocket (MBG) boot ROM		✓	Optional.
GBC boot ROM		✓	Optional. Required for color palette support for monochrome GB games.

Pokémon mini

File type(s)	Emulator(s)	Backup	Note
BIOS	Various	✓	Optional in PokeMini and minimon.

Game Boy Advance / e-Reader

File type(s)	Emulator(s)	Backup	Note
Boot ROM	Various	✓	Optional. Required for some games, homebrew, and connectivity with the GameCube.
e-Reader BIOS files	Various	✓	Required for e-Reader emulation. Including Card e-Reader (Japan), Card e-Reader+ (Japan) and e-Reader (USA).

Nintendo DS / DSi

File type(s)	Emulator(s)	Backup	Note