Wonder.me is described as 'Online gatherings that are fun - social - better - Wonder is a virtual space where people can meet and talk' and is an website in the Office & Productivity category. There are three alternatives to Wonder.me, not only websites but also apps for Self-Hosted solutions, Android and iPhone. The best alternative is Workadventure, which is both free and Open Source. Other great sites and apps similar to Wonder.me are Gather (Free Personal) and trember (Free).
Choose an avatar to roam virtual maps reminiscent of classic video games. When you meet other people within that space an WebRTC video connection will be established. Larger gatherings possible with Jitsi Integration.