The Palette files can be extended from 0-175 to 0-255 options.
This will require some fixes to the engine to really work but can be suitable for larger palette files used by scripting.
Some ideas from the community;
matte yellows that aren't faded
iirc there are good red and green gradients in the upper half (or lower in the tga), but not blue. Maybe add a group of 4 blues, not very outstanding, something you can use in medieval robes and clothes without being too striking
Need to review the current palette files for reference.