NegativeScreen!

Ever notice how people texting at night have that eerie blue glow?

LightBulb - Background application that adjusts screen gamma as the day goes, reducing blue light when it gets late

SunsetScreen is a free Windows app (for personal use) which helps take the glare off your your screen in the evening. Scientific research has shown that melatonin - the chemical the brain makes late in the day - is reduced when exposed to blue light. By tempering this blue light, it becomes easier to wind down properly at night, and thus have a more restful sleep.

Iris mini is free and minimalistic version of Iris. Small. Minimalistic. Free. Portable. Automatic. Awesome for everyone. Just double click and it will work.

Enables darker-than-dark Desktop dimming for your displays.

GoodNight is an app that allows you to directly access the screen's gamma levels, and modify it using IOMobileFramebuffer. With this you can do any of the following:

Nocturne is simple app for switching a computer to night vision mode. It has a few tricks up its sleeve: color correction, window shadow toggling, and background removal.

Night Screen helps protect your eyes from screen light on Android devices. Adjust brightness and screen color to prevent your eyes from being hurt by screen light.

Synchronize your external monitor brightness with built-in display.Application reads current brightness of your built-in display and passes it to external monitors via DDC interface.You can adjust brightness by menu in system status bar.

PC SunScreen is a powerful software app for PCs running Windows 7 or later, which automatically adjusts your screen colour to mimic natural daylight, gradually increasing the blue content from dawn to midday and then reducing it in the hours before you intend to go to bed. Research has shown that this can have a significant impact on sleep patterns.