Lumen is a menu bar application for macOS that magically sets the screen brightness based on your screen contents.

Philips Hue Automation for the Mac Desktop.
Brilliance brings the outside world into your home through Philips Hue lights. Set your location, choose what kind of lighting you want: sunlight, weather-based, urban lighting, northern lights, and more, set a schedule to turn the lights on and off, then sit back and enjoy your lights without having to fiddle with an app or dimmers.

Calise (acronym for “camera light sensor”) is a Free/Open Source python 2.x program that calculates ambient brightness and sets screen’s correct backlight using a camera.