GDevelop is an open source game creation software.

LÖVE is a framework you can use to make 2D games in Lua.

Playir is a mobile app and game creation platform, that allows you to create your own games and apps from pre-made templates.

001 Game Creator is a graphically assisted scripting engine.

Construct 3 is a game making software to develop and build games.

Urho3D is a free lightweight, cross-platform 2D and 3D game engine implemented in C++ and released under the MIT license.

Cocos2d-x is an open-source and cross platform open source free 2D game engine for mobile game development known for its speed, stability, and easy of use.