These are some of the most unusual 3D printing materials currently available on the market from dsfsdf's blog

Linen can be used in a variety of ways.
The French manufacturer Nanovia offers a composite material made of PLA and flax that can be used as an alternative to conventional filaments. According to the manufacturer, this composite material is not only a more environmentally friendly alternative to traditional filaments, but it also allows for the creation of a variety of brown shades by varying the printing parameters used to create them. A simple way to accomplish this is to alter the printing temperature during the manufacturing process. In terms of finishing, the manufacturer recommends that the printed parts be sealed with a UV protection treatment in order to ensure that the 3D printing parts last as long as possible.