Overview of different transducing mechanisms for converting different forms of energies into electricity and their respective generators for hybrid generator integration. Reproduced with permission from Refs. [65, 73, 107, 126, 132–135, 172, 177], copyright 2019 Wiley-VCH, 2020 Elsevier B.V., 2018 Elsevier B.V., 2019 American Chemical Society, 2020 Elsevier B.V., 2020 Elsevier B.V., 2020 American Association for the Advancement of Science, 2018 Wiley-VCH, 2020 American Chemical Society, and 2019 Elsevier B.V.