I'd rather not just leave the palettes, it wouldn't be very complete. I don't see where I would need all of the colours of the rainbow though, surely two browns in a dungeon Cset are better than a purple and a green or something...
Looking at Pure's level palettes, they have mostly dull tones and no bright colours like that, but I'll give it a try.
If you're downloading the tileset, do it from this link rather than any earlier ones, as they won't work (the one in my signature is to the black and white version)

FFA Tileset