Unrepublic is described as 'virtual world where users can socialize, chat in pixel art isometric environment and play games'. There are five games similar to Unrepublic for a variety of platforms, including Online / Web-based, Mac, Windows, Android and iPhone. The best alternative is Roblox, which is free. Other Unrepublic like games are Second Life (Freemium), ActiveWorlds (Free), Habbo (Freemium) and Smeet (Free).
Roblox allows you to create games, build whatever you want with lego-like bricks, play other games made by users of the community, and even participate in the economy by trading, selling, buying, and collecting items.
Second Life is a free 3D virtual world where users can socialize, connect and create using free voice and text chat. To access this world you need to use a viewer such as Second Life Viewer (see Second Life Viewer).
Activeworlds hosts a Universe of over 500 3D virtual reality worlds. In these worlds you can choose from a vast array of avatars that fit your personality (or your perceived personality - that's half the fun!).
Smeet is a virtual 3D World, where you can create your Avatar and your own Room. Start now and meet new friends, flirt, organize your party, share pictures and videos! Smeet is available in English, French, German, Italian and Spanish