Second Life - Second Life is a virtual reality platform where individuals interact in a virtual world. The software was developed in 2003 by Linden Labs. More than one million people now regularly use the software.
Agar.io - The smash hit game! Control your cell and eat other players to grow larger! Play with millions of players around the world and try to become the biggest cell of all!
Movie Star Planet - Movie Star Planet is an Online Virtual World, MMO, and RPG Simulation by MovieStarPlanet.
Slither.io - Slither.io is a multiplayer online video game. Players control an avatar resembling a worm, which consumes multicolored pellets, both from other players and ones that naturally spawn on the map in the game, to grow in size.
MySims Kingdom - MySims Kingdom is based upon The Sims series but provides special and extremely different gameplay to the original series making it definitely worth your consideration.
Diep.io - Diep.io is a multiplayer action game available for web browsers, Android, and iOS, created by Brazilian developer Matheus Valadares. Players control tanks and earn points by destroying shapes and killing other players in a 2D arena.