lua dev plugin for unreal engine 4 or 5
Arianne is an engine to develop multiplayer online games like Stendhal
8-bit Graphical API for Java
Source code of the chapters of the book 3D Game Development with LWJGL
Build Cross-platform Applications
An advanced flexible game engine for Java.
Free strategy browsergame engine.
Take the chess graphism, and use it with a chess engine.
A multiplatform game engine for interactive fiction experiences
An extensible development framework for roleplay games.
A game engine in java for 2D strategy games
AMOS BASIC reimplementation in Java