Since this thread is so useful, and very interesting, I thought I would post here rather than start a new topic.
I love the palette, but feel that it could do with a few tweaks. Here is one the versions of Arne's palettes (not sure which one now, I think v16, but with less purple in the dark blue):
My new version is below...
I think the red, blue, green and 2 dark grey/blue colours are excellent. As with what Feron said, I think the lightest blue is a little redundant. So, I've sacrificied that colour and added in a 3rd green. Although close to one of the dark blue/greys it does help take some of the greys out of the greens in the trees. Since green is so common and the colour range we are most sensitive to, I thought it was important to add a 3rd green. We still have the 2 dark colours to use and dither with the green as well. In fact we can dither the green with the dark blue to get a darker blue-green as well. The addition of a 3rd green adds a warmer colour to the mix to use as well.
I also added more contrast between the 2 medium brown/oranges as I felt they were a little too closer together.
Finally I have changed the dark grey brown into a dark purple brown. I think this helps adds a dark warm colour in contrast to the dark cold blue colours and also helps add a purplish colour to the palette. This helps remove some of the grey/blue with the images and can be used as a darker skin/flame colour (notice I've used it in the explosions). I think the addition of 2 dark but warm colours helps compliment things against the dark blue/greys and gives more options to the artist.
So, I ran the pics through promotions remap and then did some editing. I think the changes help add a little bit more dynamism to the colours. Here is the new image:
Arne's palette (HappyMonster variation #1)