Multifunctional energy harvesters that can transform a variety of ambient energies into useable electricity have been developed as a result of the search for sustainable, decentralized power sources. The design and integration of multifunctional energy harvesting systems that include piezoelectric, wind, and acoustic energy conversion processes are examined in this chapter using bio-inspired approaches. These hybrid gadgets, which are inspired by natural systems, show improved efficiency and flexibility. Innovative materials are discussed, such as bio-derived piezoelectric polymers, biomimetic surfaces for controlling wind flow, and acoustic metamaterials modelled after natural auditory organs. Alongside developments in nanostructured interfaces and self-powered sensor networks, system designs for synergistic energy coupling and storage are examined. These harvesters provide prospective avenues for self-sustaining microelectronic systems, smart infrastructures, and autonomous environmental monitoring platforms by combining biomimicry with multi-modal energy conversion.