The flexible game engine
Stride (formerly Xenko), a free and open-source cross-platform C# game
Free game engine for development of desktop, mobile, and web games
3D Game engine with editor
Descent 3 by Outrage Entertainment
High performance UI layout library in C
A game framework written with osu! in mind.
A cross-platform, open-source, pure C game engine for mobile game
3D C++ Game Engine - yet another open source game engine
A 2D game engine and level editor
Multi-platform game engine similar to old Megaman with a stage editor
A roguelike game engine/editor
3D Game engine
C++ Text Adventure Engine
A Simple Game Engine
cross-platform 2d game engine