Shodan - Shodan is the world's first search engine for Internet-connected devices.
HackerOne - HackerOne provides a platform designed to streamline vulnerability coordination and bug bounty program by enlisting hackers.
Censys - Censys helps organizations, individuals, and researchers find and monitor every server on the Internet to reduce exposure and improve security.
Intruder - Intruder is a security monitoring platform for internet-facing systems.
Exploit Pack - Exploit Pack is an open source project security that will help you adapt exploit codes on-the-fly.
Nessus - Nessus Professional is a security platform designed for businesses who want to protect the security of themselves, their clients, and their customers.