Nanofluids (NF) have recently emerged as pioneers of standard heat transfer fluid augmentation or potential replacement. The potential for NFs to be employed in a wide range of technical applications, ranging from renewable energy to nanomedicine, have become one of today's most investigated issues. The widespread use of warmth to move liquids in modern applications emphasizes their critical role in the effectiveness of the system. The various methods for determining the thermal conductivity of NFs are explained. Using hypothetical thermal conductivity (TC) models like Hamilton and Crosser, Jeffrey, Maxwell, Davis, and Bruggeman, the heat conductivity of Water, Liquid Sodium, and Ethylene Glycol possessing unique concentrations for Copper, Aluminum and Silver nanoparticles are investigated in this study. As a result, this study provides an overview of the most significant achievements and contentious discoveries in the field of NFs thermal conductivity. The findings reveal that when nanoparticles are fixed, the thermal conductivity of nanofluids increases.