Horde3D – Next Generation Graphic Engine
Horde3D is small, open Source and cross platform game engine. This 3D rendering engine is written in C++. It targets the platform of Windows, Linux and Mac OS X. Its C-style exposed API interface allows user to use it from any language possible with less effort. It thus, offers the bindings to C#, Java, Python, Lua, Go and many other languages.
HeroEngine – Cloud Based Development Tool
HeroEngine is 3D game Engine. It is a platform for all-in-one development to make and operate online games. It is written in C++, C# and HeroScript Language (HSL) and used to develop games for the platform of Microsoft Windows. HeroEngine was developed by Simutronics Corporation for the game Hero’s Journey; however the game was never released.
Gold Source (GoldSrc)- Predecessor of Source Engine
Gold Source also named as GoldSrc is a powerful 3D game engine of its time. It is written in C/C++ and mainly used for modding (modifications in code) with its mod development tools. The engine is used to develop games for windows, Playstation 2, Mac OS, Linux and Dreamcast.
Gold Box – The RPG Series of 1990s
GoldBox is a Propriety Game Engine developed by SSI (Strategic Simulation Inc.) in 1988. This engine is written in C/C++ but its initial version was written in Assembly and PASCAL. It developed games for the platforms of Apple II, Apple Macintosh, Amiga, Commodore 64, Atari ST, DOS, NES, NEC PC-9800, and Sega Genesis.
Godot Game Engine
Godot is a cross platform free and open source game engine with MIT (a light license) licensing. It is written in C++ and C# and used to develop 2D and 3D games. The development environment runs on Windows, MacOS and Linux and develops games for platforms like windows, Linux, macOS, iOS, Android, HTML5, WebAssembly and Xbox One.