melonDS
melonDS is a free and open source multiplatform emulator for Nintendo DS and DSi that provides fast and accurate emulation
GB Enhanced+ is a free and open source a Game Boy emulator
DuckStation is an simulator/emulator of the Sony PlayStation(TM) console, focusing on playability, speed, and long-term maintainability
Dolphin Emulator is a free and open source multiplatform emulator for the two latest Nintendo game consoles: GameCube and Wii