Vanity Filters

Those are filters that use various Super Secret Settings shaders. To achieve that, the mod adds those shaders back for 1.21 since they were removed by Mojang. If any other mod or datapack modifies them, those filters will use that mod's version instead. They randomly generate in various structures:

Structure	Filter
Abandoned Mineshaft	Spider Filter
Ancient City	Sobel Filter
Bastion (misc chest)	NTSC Filter
Buried Treasure	Pencil Filter
Desert Pyramid	Bits Filter
End City (treasure)	Wobble Filter
Igloo	Art Filter
Jungle Temple	Color Convolve Filter
Nether Bridge	Blobs Filter
Pillager Outpost	Scan Pincushion Filter
Ruined Portal	Flip Filter
Shipwreck (supply chest)	Scan Pincushion Filter
Simple Dungeon	Antialias Filter
Trial Chamber (corridor)	Bumpy Filter
Underwater Ruin (small)	Blur Filter
Village Temple	Deconverge Filter
Woodland Mansion	Desaturate Filter

The Bumpy filter is only naturally generated in the 1.21.1 version of the mod. In the 1.20.1 version, it's craftable instead. Use a recipe viewer like JEI to find the recipe.