This mod adds back the super secret shaders that have existed in code untill version 1.21.1. I made this pack simply to update my Origins datapacks that used those shaders and instead of simply embedding them in those datapacks i thought that others may also want a single resource pack to add them back.

Restored effects (load by id, e.g. minecraft:shaders/post/.json):   antialias   art   bits   blobs   blobs2   bumpy   color_convolve   deconverge   desaturate   flip   fxaa   green   notch   ntsc   outline   pencil   phosphor   scan_pincushion   sobel   wobble