I don't know how to describe it, sorry. Like as if they are all printed on recycling paper, perhaps? They have a touch of grayness? Or perhaps it is "all pastels", as the other comment said? Sorry I am not artist enough to be able to describe it.
Ah gotcha. Yeah there is definitely a lot of pastel palettes on there. I guess that's what I lean towards. I'll try to add more, non pastel palettes soon :)