Low-grade　heat　(below　373　Kelvins)　is　abundant　and　ubiquitous,　yet　the　lack　of　cost-effective　recovery　technologies　frequently　impedes　its　effective　utilization.　The　advent　of　thermogalvanic　hydrogel　thermocells　has　garnered　significant　attention　due　to　their　high　thermopower,　inherent　flexibility,　low　cost,　and　scalability.　Thermogalvanic　hydrogels　have　significantly　enhanced　their　thermoelectric　performance,　resulting　in　the　development　of　functional　materials　that　exhibit　flexibility,　stretchability,　self-healing,　and　frost　resistance.　However,　there　are　substantial　challenges　in　developing　multifunctional　thermogalvanic　hydrogels　that　combine　high　power　density　and　efficiency　with　practical　applicability.　This　review　discusses　the　synthesis　of　the　novel　redox　couple,　improving　the　performance　of　electrolytes　to　increase　thermopower,　creating　electrodes　with　extensive　surface　areas　for　better　current　density　and　flexibility,　and　optimizing　thermocell　structure　design　to　improve　performance　further.　This　comprehensive　review　aims　to　propel　progress　toward　higher　performance　levels　and　broader　applications　of　thermogalvanic　hydrogel　thermocells.