My Injectable Generic Camera System repo for creating custom camera tools for games: https://github.com/FransBouma/InjectableGenericCameraSystem (also contains small tools, like a dll injector, as well-known ones are often blacklisted by windows defender)
Reshade source code: https://github.com/crosire/reshade While not directly hacking related, it contains a wealth of information how to intercept DX/OpenGL api's and perform your own code instead or use it as a trigger for your own code (e.g. call your own code at Present time when a frame is rendered)