Edorble is a virtual world platform for education, based on Unity, and currently in beta. From their website:
Edorble is a cross-platform application for Mac, PC, HTC Vive, and Oculus Rift that lets you gather in 3D environments with your peers or colleagues. These environments let you use in-world web browsers, break into small groups, use gestures, and explore. You can either use our pre-made environments, or you or your students can use the Edorble Creator Tools for Unity 3D to design your own 3D environments (see next question).
Beyond Edorble, We also create custom 3D/VR applications for clients in the education/training space, and we offer in-person and online courses and professional development at Edorble Academy.
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While Edorble is in beta, it’s entirely free so long as you are using it on a small scale (20 or fewer simultaneous users in your world). When we leave beta, we’ll have an affordable, monthly subscription model that gives you access to larger-scale usage, premium features for the creator tools, and more. If you want us to design a custom build of Edorble with specific designs, features, or integrations, we also do that as a service.
Here’s a year-old, one-minute video that gives an overview of what Edorble looks like (unfortunately, there’s no sound):
I couldn’t find any recent videos about Edorble, which leads me to wonder if the project has stalled. I also note that the Edorble blog hasn’t been updated since September 2017. It looks like it’s a project that never made it out of beta.