Mame is the most comprehensive emulator you'll ever get. They emulate everything under the sun: from very obscure computers that you don't even find info on the internet to mechanical car rides (yes they even preserve the roms for those).
Yeah, it's absolutely amazing and noble, especially for us that are into those things (Personally, I have a vast collection of consoles and games, including full SNES library etc.). Wikipedia, Internet Archive + Common Crawl, Emulation scene with now MAME at the forefront - those are Alexandria of our times.
Slot machines too.
Yes, I’ve been running the Apple LaserWriter emulator to explore the internals of the original PostScript interpreter.