RetroArch is a frontend for emulators, game engines and media players.
A cross-platform PSP emulator
The game engine for everyone
Mangos ZERO is a server for World of Warcraft
Set of Python modules designed for writing video games
An iOS & tvOS Frontend for Multiple Emulators
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
New Godot bindings for Swift
The ioquake3 community effort to continue supporting/developing id's
ThinkPHP Framework
Homebrew development library for Nintendo 3DS/Horizon OS user mode
Open source library for creative expression on the web, desktop, etc.
Mod manager for the video game RimWorld
C# application with primary purpose of farming Steam cards
Stride (formerly Xenko), a free and open-source cross-platform C# game
dhewm 3 main repository
3D Engine c++
An Ubuntu remix for both new and experienced Linux sophisticates
A MUD client for Android, iOS, Linux, Mac OS X and Windows
kernel mode mouse accel
GemRB is a portable open-source implementation of the Infinity Engine
Zoomable user interface (ZUI) with file manager, file viewers and more