Shades - Shades is a FREE utility for controlling the brightness of your screen.
CareUEyes - CareUEyes is an eye protection software for windows that comes with blue light filter, screen dimmer, and break reminder
Simple Screen Shade - Description and screenshots of Simple Screen Shade.
Dimmer - A very small and free utility for Windows to reduce brightness on LCD/TFT screens.
ScreenDimmer - Having two monitors on OSX is both a joy and a pain.
CF.lumen - CF.lumen is a powerful app for Android that adjusts the colors by detecting the position of the sun or according to custom settings.