Full disclosure I have used xray hacks and mods in the past. However, I used fullbright far more than the xray. Does anyone know of a texture or shader that does the same without being a hack or cheating? I saw none for 1.13. I basically just want nightvision at all times. I do not want to get an xray client or mod, as I just joined a server that is very strict on that.
The Meaning of Life, the Universe, and Everything.
When you open your .minecraft folder there should be an options.txt file you can open and edit. Like the 4th option down will be gamma:1.0 (or something similar) and changing the gamma value to gamma:1000.0 will make every block in your field of vision fully illuminated. A number lower than 1000 will likely work but that's what I stick with when I need such things.
There's an alternative approach to this, if you have Optifine:
1) make a new folder and put it in your resource pack folder. Name it whatever you want.
2) add a pack.mcmeta-file to it with the following text:
"description": "I want to cheat"
3) add the following folders: assets -> minecraft -> optifine -> lightmap
4) inside the lightmap folder put a 32x32 png-image named "world0" which is completely white.
5) repeat above step with "world1" and "world-1", if you want the effect for nether and end.