lua dev plugin for unreal engine 4 or 5
SDL based generic 2D game engine
The imaginary eight-bit machine
A cross platform Lua based game engine
8-bit Graphical API for Java
Build Cross-platform Applications
3D .NET engine for Windows, Linux, Mac
Flexible and easy-to-use 2d game engine
Free strategy browsergame engine.
A generic 2D engine for any kind of game
A world editor for HGE game engine written in python and uses OpenGL.
Make games with Lego-like building blocks
An extensible game engine that targets RPGs.