In the present scenario, the energy crisis and environmental burden have become two major problems due to the mismanagement of thermal power. The tremendous amount of waste heat from various energy sectors can be utilized by thermoelectric generators as a green energy resource. Thermoelectric generators (TEGs) generally exhibits enormous potential for converting waste heat to electricity without involving any mechanical vibrations and noises. The expensive manufacturing techniques, low reliability, and availability of conventional thermoelectric materials have immensely attracted researcher’s interest in scavenging advanced new thermoelectric materials (TEMs). Recently, the promising thermoelectric properties of organic and inorganic nanomaterial-based hybrid nanocomposites have gained popularity among researchers. The engrafting of conducting organic and inorganic thermoelectric nanoparticles onto graphene/CNTs matrices combines the advantage of both inorganic and organic materials. The present review comprehensively emphasizes on new hybrid nanocomposite-based TEMs used specifically for wearable TEGs. To encounter the performance requirement of these TEGs, we provided material synthesis methods, fabrication techniques and possible mechanisms in detail. For comparison purpose, few traditional TEMs have been also reported with the addition of current and potential advanced general applications of TE materials in the form of rigid and wearable devices.