scene-oriented, flexible 3D engine (C++, Python, C#, Java)
A .NET ascii/ansi console engine written in C# for MonoGame and XNA
Full featured MUD server with all the trimmings.
PyCAPGE - Python Classic Adventure Point and Click Game Engine
A game engine for console based text games
A space race game in the style of A Dark Room
A 3D game engine in java.
An online multiplayer turn based strategy game and board game engine.
Java decentralized cross-platform network multiplayer game engine
2D physics engine for games
A multiplatform game engine for interactive fiction experiences
C++ Text Adventure Engine
Free Android 2D OpenGL Game Engine
Role Playing Game Engine
Java Client + JS/Canvas Server-Side System, with maintained Objects
Free MMORPG Engine. Develop and host graphical browser-based games.
MKEngine is a game engine for Text-Based games.