You can make it - Open Source MMORPG Platform
FiveM is a modification for Grand Theft Auto V
Set of utilities for Opensim servers running on Linux
Framework for producing web-based database applications
Playing Go with web-based turn-based Go server
Based on the raedwulf-et project
A suite of tools for any RPG system
Make containers fly - FlightGear scenery containerized
DarkForest, the Facebook Go engine
Massively multiplayer online game server and client framework
a Human and Artificial Intelligence Network
An extensible development framework for roleplay games.
Operating System for gaming, working, writing and browse the web +mail
Zap Engine