An iris is round in shape and colored part of a person’s eye. Iris’s characteristics are unique in every person, and therefore, it distinguishes one person from others. Several recognition systems exist in the biometric verification system, like face, voice, Iris, and finger. But Iris has a crucial role in authenticating or recognizing a human being. Generally, the iris recognition arrangement is associated with specific top expensive applications where security is paramount and uses a delicate infrared illumination camera to capture images. Even in the same person, the texture of the left and right eye is not similar. It differs even among the twins’ eyes, making it an extra secure way to automatically identify a person than other recognition systems. In the review paper, we highlight several existing iris datasets on iris recognition. Moreover, image preprocessing processes and segmentation techniques can be practically used to iris datasets and feature extraction methods, which will be used as input for any machine learning technique to identify the individuals efficiently.