Open Cobalt is described as 'Alpha is the first step in a long term project to make available to all people a free and open source platform for constructing, accessing, and sharing virtual workspaces for research and education' and is an app in the Social & Communications category. There are three alternatives to Open Cobalt for a variety of platforms, including Windows, Mac, Oculus Experiences, Oculus Rift and Online / Web-based. The best alternative is Second Life, which is free. Other great apps like Open Cobalt are IMVU (Freemium) and Facebook Horizon (Free).
In Facebook Horizon, not only can you explore the virtual world as it grows and changes, but you can discover all sorts of new things that interest and inspire you. Experience gravity defying, distance spanning, genre bending games of all types.