CareUEyes - CareUEyes is an eye protection software for windows that comes with blue light filter, screen dimmer, and break reminder
Dimmer - A very small and free utility for Windows to reduce brightness on LCD/TFT screens.
Simple Screen Shade - Description and screenshots of Simple Screen Shade.
Nocturne - Nocturne is simple app for switching a computer to night vision mode.
PangoBright - Screen dimming software that allows you to control the brightness of your laptop screens as well as external monitors.
Shades - Shades is a FREE utility for controlling the brightness of your screen.