Recs.
Updated
Roblox was released in 2006, which was a few years earlier than Minecraft, and focuses more on creating games. Young game developers get to practice and expand their creativity. Players are encouraged to interact and explore. With 30 million active monthly players, Roblox is certainly growing as fast as the people who uses it.
Specs
Pros
Pro The game is free to play
You'll be able to create your own games and play without paying for anything. Though they do have virtual currency that they call Robux, which you have to buy with real cash. You only have to do so if you want to upgrade the look of your avatar or get optional in-game power-ups. Like with most games, if you have the patience you can additional items over time, then you don't have to spend a dime.
Pro Enjoy creating and playing your own game or thousands of other games available
You can create your own original game and play it, and have others play your game too. As of 2017, Roblox has over 500,000 game creators designing games. That's a lot of games made by players like you, so you'll never run out of options on what to play.