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 an online virtual world, developed and owned by the San Francisco-based firm Linden Lab and launched on June 23, 2003.
OpenSimulator is an open-source server platform for hosting virtual worlds and the Metaverse. It is largely compatible with the virtual world Second Life but compatibility is not a design goal.
Tired of the roblox tyranny and greed? The Novetus community game is the solution! Novetus was made to improve on RBXLegacy, with the addition of new features that enhance the launcher for mod development, player customization, and overall usability.
IMVU is a 3D based social network using avatars, with user created rooms and high levels of avatar and room customisation. (Room creation requires the PC or Mac client).
In Twinity's free 3D world and 3D chat community, you can create your own avatar, party with friends, dress-up, go shopping and interact via 3D chat and animations. Get creative and design your virtual apartment in an authentic real virtual city or create your own island to...
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!).
Struckd is the next-generation gaming platform for user created content where people of all ages come together to create, share and play games. Create your own games and play thousands of others. Download for Mobile & Desktop: www.struckd.com.
Struckd - 3D Game Creator vs vSide opinions
It's much more related to Roblox than Vside in overall experience. Not a bad app, it's just not comparable.