Nestopia - A portable and cycle-accurate NES emulator written in C++
itch.io - An online game marketplace and community.
FCEUX - FCEUX is a Nintendo Entertainment System (NES), Famicom, and Famicom Disk System (FDS) emulator.
GOG.com - DRM-free game store, selling both new and old titles. No clients required.
puNES - PuNES is a high accuracy NES emulator.
Ubisoft Club - Ubisoft Club app enables you to get updates about your favorite games timely.