This is my section of emulators I run or have run on my Linux system. I only test on Linux machines and specifically on openSUSE Linux. Your mileage may vary if you are running anything else.
Nintendo Entertainment System/Famicom emulator
Nestopia is a cycle-accurate NES/Famicom emulator. It has a high compatibility rate and support for many peripherals and input devices. It works very nicely. It has a very straight-forward interface and allows for five save states.
If you should happen to mess up your configuration, the files are stored under:
My specific issue was that I put the program in full screen mode and could not exit the mode. The configuration file for Nestopia is:
Search for fullscreen and change the value to 0 if you too stumble up on this.
Portable, freeware Super Nintendo Entertainment System™ emulator
Snes9x is a portable, freeware Super Nintendo Entertainment System (SNES) emulator. It allows you to play most games designed for the SNES and Super Famicom Nintendo game systems on Linux. Additionally, this package contains a very nice, intuitive graphical front-end making the use of snes9x a lot less difficult.
Multi Architecture Emulator with numerous backends
This has been my favorite retro gaming emulator. Not in the official openSUSE repositories but it works very well and it has brought me many hours of enjoyment. However, as of late, it hasn’t been working as expected. I to test it from time to time but lately I have not been able to get it to run properly.
This is a great emulator for all things GameBoy, GameBoy Color and GameBoy Advance. It is easy to install as a Snap or to download and compile it yourself.