Sublist3r - Sublist3r is a python tool designed to enumerate subdomains of websites using OSINT.
HackerOne - HackerOne provides a platform designed to streamline vulnerability coordination and bug bounty program by enlisting hackers.
SpiderFoot - Open source intelligence (OSINT) automation tool.
Intruder - Intruder is a security monitoring platform for internet-facing systems.
sn0int - sn0int is a semi-automatic OSINT framework and package manager
Forcepoint Web Security Suite - Internet Security