I'm not much of a coding expert, so please let me know if this isn't feasible, but Nash's CBlood gave me an idea that I've been meaning to suggest for months. While CBlood works perfectly with stock Doom, some mods that replace the palette like the BTSX series render some blood colors looking off (for example, the cacodemon's blood color is set to a deep blue, but BTSX's death sprites for the monster gives it a far lighter blue).
I wanted to suggest a feature for GZDoom such as a lump file or an addition on GAMEINFO or anything that allows a pk3 file to load data off of a folder based off of a file's checksum. For the example I've mentioned, CBlood could have a way to detect btsx_e1a.wad, the first main file for the latest version of BTSX Episode 1, using CRC32, MD5, or another method to load a folder of the same string and get files from there. This way, the blood color for the cacodemon and other monsters can be changed for BTSX without affecting any other mods or files.
If something similar has been requested or if I'm being unreasonable with the code required for this feature, please feel free to shoot this idea down. I'd just figure that it would be useful for mod authors who'd wanted to apply maximum compatibility with other addons.