- Aether3D (C++, zlib, beta)
- Allegro (C, zlib, mature)
- Blip Engine (C, Lua, Apache-2.0, beta)
- COCOS2D-X (C++, MIT, mature)
- Crystal Space 3D SDK (C, C++, LGPL-2.1, mature, inactive since 2015)
- Dash Engine (D, MIT, mature, inactive since 2015)
- Delta Engine (C#, Apache-2.0, mature, inactive since 2015)
- DeSmuME (C, C++, GPL-2.0, mature, inactive since 2015)
- ENIGMA (development environment) (C++, C, GPL-3.0, mature)
- F.LF (JavaScript, CC-BY-NC-SA-3.0, mature)
- flixel-gdx (Java, 3-clause BSD, beta, inactive since 2017)
- Flixel (ActionScript, MIT, mature)
- GBDK (C, Assembly, C++, MIT, mature)
- Gideros (C, C++, Lua, ?, mature)
- Grit Game Engine (C++, Python, MIT, beta)
- HaxeFlixel (Haxe, MIT, mature)
- HaxePunk (Haxe, MIT, mature)
- Irrlicht Engine (C++, C, zlib, mature)
- JiGS Interactive Game System (JavaScript, PHP, TypeScript, GPL-3.0, beta)
- jMonkeyEngine (Java, 3-clause BSD, mature)
- libGDX (Java, C++, C, Apache-2.0, mature)
- Lightweight Java Game Library (Kotlin, C, Java, 3-clause BSD, mature)
- LIKO-12 (Lua, Rust, MIT, mature)
- Love2dCS (C#, C++, MIT, mature)
- Lumix Engine (C++, MIT, beta)
- LÖVE (C++, zlib, mature)
- Mana (C++, GPL-2.0, beta)
- Maratis (C++, GPL-2.0, beta)
- MonoGame (C#, MS-PL, MIT, mature)
- Moondust Project (C++, C, GPL-3.0, beta)
- Nazara Engine (C, C++, MIT, beta)
- O.H.R.RPG.C.E. (Basic, GPL-2.0, mature)
- Octaforge (C++, Custom, mature)
- OGRE (C++, MIT, mature)
- Omega-rpg (C, Emacs Lisp, LGPL-2.0, beta, inactive since 2000)
- Open Game Engine (C++, LGPL-2.1, beta, inactive since 2008)
- Open RPG Maker (C++, GPL-3.0, beta, inactive since 2014)
- OpenFL (Haxe, MIT, mature)
- OpenRPG (Python, GPL-2.0, mature, inactive since 2013)
- Overload (C, C++, MIT, mature)
- Panda3D (C++, C, 3-clause BSD, mature)
- Phaser (JavaScript, MIT, mature)
- PLIB (C++, LGPL-2.0, mature, inactive since 2012)
- Polycode (C, C++, MIT, beta)
- pygame (C, Python, LGPL-2.1, mature)
- pyORPG (Python, MIT, beta, inactive since 2015)
- pyRacerz (Python, GPL-2.0, beta, inactive since 2005)
- Quad-engine (Pascal, MIT, beta)
- raylib (C, C++, C#, zlib, mature)
- rpge (C, Script, GPL-3.0, beta, inactive since 2014)
- sandbox Game Maker (C++, C, Custom, mature, inactive since 2014)
- Scrolling Game Development Kit 2 (C#, GPL-2.0, mature, inactive since 2017)
- SDL Game Engine 2D (C, MIT, beta, inactive since 2014)
- SGE Game Engine (Python, LGPL-3.0, mature, inactive since 2017)
- SoftPixel Engine (C++, C, zlib, mature, inactive since 2013)
- Solar2D (C++, MIT, mature)
- Solarus (C, C++, Lua, GPL-3.0, mature)
- Storm Engine (C++, GPL-3.0, mature)
- Superpowers (TypeScript, ISC, mature)
- Urho3D (C++, AngelScript, MIT, mature)
- VASSAL (Java, LGPL-2.1, mature)
- Vortice (C#, C++, MIT, mature)
- VQEngine (C++, GPL-3.0, beta)
- xoreos (C++, GPL-3.0, beta)
- ZGameEditor (Pascal, MIT, mature)
- ZQuest Classic (C++, C, GPL-3.0, mature)