In this study, we investigated the usability of new powdered additives in the paperboard industry. We manufactured the powdered additives from peanut husks and garlic stems by grinding. The chemical composition, particle size, particle size distribution, and particle shape were investigated to identify the basic properties of the powdered raw materials. To determine the effect of the powdered additives on paper properties, handsheets were prepared by adding the powdered additives to the pulp slurry. The chemical composition, such as the contents of holocellulose, lignin, and ash, showed similar values to those of other biomass materials. The particles of peanut husk powder were irregularly shaped, smaller, and had a broader particle size distribution than those of the garlic stem powder, which had the fibril form. The particles of the two powdered raw materials showed a positioning of expansion in the fiber network, resulting in increased bulk and a loss of strength. Handsheets containing garlic stem particles were stronger than handsheets containing peanut husk particles. Finally, the new powdered additives are beneficial to the bulk of paperboard.