Chipboard is a great post-consumer product. Made from recycled scraps, it generally has a brown hue but can also range into the brown/gray arena. The board we use is .30 but we can get thicker stock if requested.
It’s durable, thick, and has the rugged feel of something that is definitely recycled.
3/3 spot with a full wash of blue on one side
Get a quote on something like this here