Aurora GSI for Minecraft is a client-side only Forge mod that sends game variables from Minecraft to the Aurora keyboard lighting software. Aurora can then use these variables to change the lighting on individual keys on your RGB keyboard, such as making a health bar or experience bar. The official Aurora GitHub page, which contains a list of compatible devices, is here. Make sure to download Aurora, this mod achieves nothing without it.
Description of Aurora-RGB:
https://www.project-aurora.com/
Aurora is an open-source unified keyboard and mouse lighting software that supports many different brands of keyboards including Logitech, Roccat, Razer, Corsair and more. It is highly customisable and provides an unprecedented level of control.

For those curious, this mod works by sending JSON-encoded data to the HTTP server built in to Aurora. The data that is sent to Aurora includes health, armor, death state, XP, food & saturation, player burning, some player status effects, world time and rain strength.
Example JSON sent to Aurora:
{
"provider": {
"name": "minecraft",
"appid": -1
},
"player": {
"inGame": true,
"health": 20,
"maxHealth": 20,
"absorption": 0,
"isDead": false,
"armor": 0,
"experienceLevel": 9,
"experience": 0.27999994,
"foodLevel": 19,
"saturationLevel": 0,
"isSneaking": false,
"isRidingHorse": false,
"isBurning": false,
"isInWater": true,
"playerEffects": {
"moveSpeed": false,
"fireResistance": false,
"poison": true,
"absorption": false,
"blindness": false,
"regeneration": false,
"moveSlowdown": false,
"confusion": false,
"wither": false,
"invisibility": false
}
},
"world": {
"worldTime": 26000,
"isDayTime": true,
"isRaining": false,
"rainStrength": 0
}
}
The git repo for this mod can be found on GitLab.

