I have been using colour as a form of expression in many of my animations before:
The main colour here is green and it creates an eerie, almost Halloween-y atmosphere.
Blue was used here to show a ghostly or supernatural presence. (just don’t pay attention to the cut off prevention)
The firey golds and oranges here echo the colour of the character’s eyes and compliment their colour schemes nicely.
In my animated book adaptation, “The Rise of Scourge”, I chose a different colour scheme for each location. The house is a loud and unnatural lilac that was similar to that of Tiny’s collar, showing his connection to the house. The “middle-ground”, or the area between the fence and the forest is a dirty maroon, which is somewhere in the middle of the lilac of the house and the red of the forest, The dirtiness of the colour comes from the negative associations with the area including the mocking scorn of the Housecats and when Tiny lies injured and heartbroken by the fence after being attacked. The forest is originally a shining gold, showing how much Tiny treasures the forest. He sees it as the most wonderful thing in the world. The forest then turns harsh red when Tigerpaw attacks representing blood (which is also repeated in Tiny’s collar which gets bloodstained.)