Okay, I downloaded the old Q2 Test from 1997, opened pak0.pak with PakExplorer (haven't done that in 23 years probably) and every object and character in the game uses .pcx files for textures, which makes them all 8-bit with a pallet. The scenery textures seem to be .wal files, which may or may not be 256 color, but I'm inclined to think that they would be, because full color textures would have been a waste of video memory back when cards had so little memory and bandwidth to spare. The only textures that have different versions are the skyboxes which very plainly have .tga and .pcx versions. All of the pieces of the .pcx skyboxes come out to 551KB in file size, where as the .tga ones are a whopping 1.12MB.
One interesting thing to note is that all of the skybox pcx files seem to be using the same pallet, and it is a generic one that has many colors that are not used in the skybox at all, so apparently it had to use some kind of universal palette. This is why the 8bit version looks SO bad... because it is really only utilizing between 22 and 129 colors (PSP 7 can count them for me) out of a 256 color pallet. The sky-only ones (straight up) are only using 22 shades of red\black\white, leading to lots of banding. Even the monster and object models in the game mostly use the same palette as the sky boxes.
One more thing I see is that there are lots of sprites and they are all paletted .pcx files as well, with a single color background for transparency. I don't recall if the game ever even uses these though since basically every effect is either a tiny (terrible looking) 3D model, or a simple dot particle effect. Presumably, if it did use these, then anything that attempted to upsample the 8bit textures to 24bit would break these transparencies and every sprite would be a square... correct?
EDIT: This is only somewhat related, but I also stumbled upon this...https://quakewiki.org/wiki/Quake_palette
Sorry if this is all starting ramble, but my point is that it seems like either I am not understanding what the lack of "8bit paletted texture" support truly does, since Riva 128, TNT and TNT2 cards could happily run Quake II or GLQuake, despite the games using almost exclusively 8bit textures... or the problem is far more specific than a video card absolutely having zero support for textures that had palettes. In the latter case, I think some of the information on the wiki should be updated because it makes it seem like 8bit textures are some kind of oddity that certain video cards have problems with... when it was actually far more common for textures to be in 8bit formats throughout the '90s. 3D acceleration didn't end this trend because 24bit textures would be unnecessarily large for such early hardware to handle... so presumably, any video card that could run contemporary games in the late 90s had some kind of support for 8bit textures... and 8bit textures all have palettes.
... does anyone see what I'm getting at? 😮