FCEUX - FCEUX is a Nintendo Entertainment System (NES), Famicom, and Famicom Disk System (FDS) emulator.
RetroArch - RetroArch is a frontend for emulators, game engines and media players.
Nestopia - A portable and cycle-accurate NES emulator written in C++
Snes9x - Snes9x is a portable, Super Nintendo Entertainment System (SNES) emulator.
BSNES - bsnes is a Super Nintendo (SNES) emulator focused on performance, features, and ease of use.
VirtuaNES - VirtuaNES is Famicom/NES emulator for Win32.