6/10 are Game Engines, the other 4/10 are tools for various things. This is not a list of everything I use, however these sound appealing enough to me that I probably would at least try them out :]
A shader testing tool, and collection of other tools and libraries for shaders Shaderc's Github Page
3D game engine, allows the dev to make "cinema quality 3D worlds", with "no fees or commercial obligations", just overly fancy way of saying free o3de on github
"Real-time physically based rendering engine" for many platforms, like Android, Linux, Windows, etc. Made specifically with Android in mind, so made to be as efficient as possible on it. Filament's Github Page
Several libraries to help aid VFX software dev Cortex's Github Page
Very unlike literal C4(the explosive), instead is an engine used for game across many platforms, i.e. Xbox, Playstation, and PC C4 Engine's Site
Toolset for gamedev, allows "rapid prototyping", which I presume it allows for quick tests, like playing the game while making it in real time Gamebryo's Site
A 3D game engine, written in C++ & C#, with wonderful graphics and strong scripting capabilities FlaxEngine's Site
A seemingly active updating game engine with plenty of documentation CRYENGINE's Site
Allows for creating unique "experiences" for the larger game/host of games Roblox, with some default assets, and ability to make your own Roblox Studio's Site
A much larger game engine as of now(9/6/25), but was and kind of still is one of the underdogs for game engines Godot's Site