Game Oldies is an online emulator website and community that lets you play your favorite childhood classic, and simply enjoying the experience, They support games for NES, SNES, Sega Master System, Sega Genesis, and much more.
Free 80s Arcade is a website where you can find arcade games from the 1980's that people used to play in the Pong Console, Atari 2600, Colecovision, Intellivision, and the Nintendo Entertainment System (NES).
Retrogames is a great way to play old school games completely online and without downloading. Here you will find a lot of different games, from almost any platform like SEGA, NEO-GEO, PSX, Mega Drive, Atari, SEGA CD...
Restrogames.cc is a website where you can play many different retro games like Super Mario Bros, Pokemon Emerald, Marvel vs. Capcom, Contra, Metal Slug 6, Aladdin, Megaman VII, Super Contra, Gals Panic, and many more.
RetroGames.cz is an amazing website to play retro video games online. Contains emulators for operating system MS-DOS and classic consoles as Atara 2600, Nintendo Entertainment System or Sega Genesis. You can be found legends as Donkey Kong, Super Mario, Sonic, Pac-Man and many others.