Classic America's Army
GameServer is a sophisticated, game server designed for online games
Visual Basic 6 2D online adventure game engine
LGSL (Live Game for PHP 5.4-8+: online status for various gameservers
Free and open source Avatar Webgame made by Vietnam
oGame-like browser space realtime strategy game based on xNova
Free Minecraft Servers tweaked for a lag-free experience!
Text Browser-Based MMO is a project with with forum integration.
Cosmos Tycoon is a open source transport simulation browser game.
starrydb is game server engine
JAVA websocket implementation for a bomberman-like game
A Kingpin Mod - Blood Money 616
web cms for clans and esport related pages
Charlotte's Utilities mod for Minecraft Forge made by Sharshar
The original Xivio.com World Server Core
Minecraft private Skin Center
Open Source Virtual World and MMOG Development Platform
Non-Java Minecraft Classic Server Software
Modular Minecraft server plugin - commands, events, ...