Here are some example images that depict the style I am looking for in the Fogbound RPG. The image above was a sample of concept art that I applied a red filter and fog to see how it would look with the Fogbound feel of the rolling toxic Red Fog. I was quite impressed with the result.
I really love the simplicity of concept art and getting the gritty feel that this sort of art imparts is essential in my opinion.
Here are some more beautiful examples of the sort of styles I want to get into the book.