Nanofluids, comprising nanoparticles and a base fluid, have captured substantial interest due to remarkable enhancements in thermal conductivity and other crucial thermophysical properties. These advancements facilitate diverse applications across various industrial processes, including biomedical and drug research. This review centers on non-Newtonian nanofluids, which diverge from Newton's law of viscosity, rendering them more adaptable and versatile. Through a comprehensive examination of the latest research, preparation methods, including both one-step and two-step techniques, and their formulations in oil-based, water-based, and ethylene glycol-based solutions are systematically explored. The study synthesizes findings that highlight significant improvements in heat transfer efficiency and introduces novel applications in sectors, such as biomedical engineering and energy systems. Furthermore, an in-depth characterization of non-Newtonian nanofluids is provided, covering their rheological, dispersion, transport, magnetic, optical, and radiative properties. These fluids are increasingly utilized in heat exchangers, automotive radiators, engines, solar collectors, and electronic coolants, demonstrating their broad spectrum of practical applications. This review shows that the ongoing challenges are primarily centered on the preparation, stability, and commercialization of non-Newtonian nanofluids. Conclusively, the paper underscores the potential of non-Newtonian nanofluids to revolutionize various technological areas and advocates for continued research to develop more stable and efficient formulations, paving the way for innovative industrial and scientific applications.