Boosted Brightness is a simple clientside mod that allows you to set your brightness beyond default levels to your liking. It makes use of Fabric (not Forge) and is compatible with Minecraft 1.19.
New Brightness Slider

The mod modifies the brightness slider in video settings, extending brightness range from 0% through 100% to -100% through 1200%.
200% to 500% gives a great balance between seeing differences in lighting and seeing well in the dark.
-50% to -100% is great for a more challenging caving experience.
1200% is full-bright.
Up to 5 Custom Brightness Levels

By default, there are 2 brightness levels: your existing brightness and 1200%.
Add up to 3 additional brightness levels for every situation: caving, nighttime, full-bright, or super-dark.
Access these sliders using Mod Menu.
New Keybinds

Use keybinds to select particular brightness levels. If you press the keybind of the currently selected brightness level, the brightness is switched to the last used brightness level.
Use the raise/lower keybinds enable quick brightness changes in-game.
If you have two brightness levels, the "Select Next Brightness" works just like a toggle between the two brightnesses.
The screenshots below compare various brightness settings in different situations.
Cave brightness comparison
Underwater brightness comparison

Missing v2 features but still useful!
1. Install Fabric
2. Drop the Fabric API jar into the mods folder
3. Drop the Boosted Brightness and Mod Menu jars into the mods folder
Works with Optifine and Sodium. Let me know if you find any compatibility issues.
MIT. Feel free to use this mod in any modpack.
No files available for download.