Another very useful tool for information gathering and OSINT, included by default in Kali Linux, is Maltego (https://www.paterva.com/web7/buy/maltego-clients/maltego-ce.php), a favorite of many penetration testers. This tool provides a graphical user interface that displays all of the analyzed elements (email addresses, people, domain names, companies, and so on) within a graph where the relationships between elements are visually shown. For example, the node representing a person will be connected by a line to that person's email address and that email address to the domain name it belongs to.