The current study focuses on development of biomass filled polymer composite feedstock formulations for a low-cost desktop fused deposition modeling (FDM) 3D printer, using wood flour (WF), a by-product of the forest industry, and polylactic acid (PLA) as the matrix. A specific plasticizer has been incorporated into the composite formulation to enhance the reinforcement capability of WF (50 wt%), improving the coilability of filament, and continuous printability of the provided filaments without nozzle clogging issues. Such advancements, especially in WF:PLA composites, are key to expanding the application of 3D printing in high-demand sectors such as construction and automotive, aligning with global sustainability efforts by conserving wood resources and reducing the impact of fossil fuel-based plastics. This research illustrates how custom material solutions could significantly enhance 3D printing capabilities, paving the way for more sustainable, efficient, and versatile manufacturing practices.