Apps similar to Gamma Dimmer include f.lux, which is free. Other options are Redshift, Twinkle Tray, Solace and LightBulb. Screen Dimmers like Gamma Dimmer are a crowded field, with more than 50 alternatives for Windows, Mac, Linux, Android and iPhone.
Shady puts a shade over your screen to help soothe your tired or dazzled eyes. You can use it to reduce your Mac's brightness far below the usual minimum, without any risk of damage to your screen.
United Kingdom
Multiscreen Blank v2 is an easy-to-use utility that allows you to independently blank out or dim one or more monitors connected to your computer, as well as mirroring the contents of screens that are physically located in another room or turned off.
Simple Screen Brightness is a small portable application written in C# that allows you to adjust the brightness for all of your connected monitors using a slider without having to use their difficult-to-use built-in menu systems.
SunshinePal is your daily sunlight companion designed to help you track your exposure, set healthy goals, and reconnect with nature for better sleep and mood.
Thailand
A Python program that calculates ambient brightness and sets screen's correct backlight using a camera.
Lumen - magic auto brightness based on screen contents. You control Lumen simply by using your brightness keys - it'll automatically learn your preferences.
United States
Monitor Bright reduces with a simple trick the monitor brightness. Useful to use the PC at night without getting blind if the minimum brightness that can be obtained adjusting monitor settings is still too high if compared to ambience brightness. Supports multi monitor systems.
Italy
EU
Focus view, extra brightness, ambient glow, and keep awake — all from your menu bar. JoyScreen transforms how you use your Mac.
PolandEU
LiteBright is a lightweight native brightness controller for Windows 10 and 11. It lets you control brightness across multiple monitors from the system tray, adjust displays independently or together, and use global keyboard shortcuts for quick changes.
Small GTK GUI application to set contrast, brightness and gamma for wayland compositors which support the wlr-gamma-control protocol extension. Basically this is the example from here: https://github.com/swaywm/wlroots/blob/master/examples/gamma-control.
