The article reviews how different types of plant materials and treatments affect the production of bio-oil for renewable fuels through fast pyrolysis. Woody biomass is commonly used due to its high-quality bio-oil, but availability and cost vary by region. Mixing different feedstocks and using pretreatments can help create a consistent and cost-effective biomass supply for biofuels. However, the impact of plant material and treatments on bio-oil yield and quality is not fully understood. The review summarizes current knowledge on how feedstock and pretreatments influence bio-oil production.