GLFW is described as 'Open Source, multi-platform library for OpenGL, OpenGL ES and Vulkan development on the desktop. It provides a simple API for creating windows, contexts and surfaces, receiving input and events' and is a game development tool in the development category. There are more than 10 alternatives to GLFW for a variety of platforms, including Windows, Linux, Mac, Web-based and iPhone apps. The best GLFW alternative is Godot Engine, which is both free and Open Source. Other great apps like GLFW are microStudio, Bevy Game Engine, UPBGE and DirectX.
Crystal Space is a mature, full-featured Software Development Kit (SDK) providing real-time 3D graphics for applications such as games and virtual reality. It is free (LGPL) and cross-platform (Windows, GNU/Linux, Mac OS X).
