The cobalt is the famous element of the D Block. These particles have a spherical morphology and their appearance is like grey or black powder. Similarly, these nanoparticles have the capability to absorb electromagnetic waves. The magnetic fluid of the nanoparticles provides the best properties for more applications. Apart from this, it has a wide range of applications such as medical equipment, shock absorption material, and sealants. In addition, it is also used in medical equipment. There are more applications in which these cobalt nanoparticles are used such as electromagnetic-wave absorption, drug delivery agents for the sake of cancer therapies, Ferrofluids, Cobalt nanoparticles inks, and Medical sensors. In the same manner, these particles can be used in the applications of high-density magnetic storage, electromagnetic wave radiation shielding for cellar phones. Last but not least, these cobalt nanoparticles are also used in magnetic resonance and biomedicine. Thus, Cobalt nanoparticles have a wide range of applications.