Agricultural waste represents a significant global challenge, with approximately 998 million tons generated annually worldwide. The bioconversion of these waste materials into value-added fermented products offers sustainable solutions for waste management while creating economic opportunities. This comprehensive review examines the potential of various agricultural residues including crop straws, fruit pomaces, vegetable wastes, and processing by-products for transformation into high-value products through microbial fermentation. We analyze current biotechnological approaches, fermentation strategies, and emerging technologies that enable the conversion of lignocellulosic and organic waste materials into biofuels, biochemicals, food ingredients, and pharmaceutical compounds. The integration of circular economy principles with advanced bioprocessing technologies presents unprecedented opportunities for sustainable agriculture and industrial development.