This section is incomplete and more here to come… one day.
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.
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 is 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.