Tenable.io VS ZoomEye

Qualys - Qualys helps your business automate the full spectrum of auditing, compliance and protection of your IT systems and web applications.

Shodan - Shodan is the world's first search engine for Internet-connected devices.

Nessus - Nessus Professional is a security platform designed for businesses who want to protect the security of themselves, their clients, and their customers.

Exploit Pack - Exploit Pack is an open source project security that will help you adapt exploit codes on-the-fly.

AlienVault USM (from AT&T Cybersecurity) - AlienVault USM Anywhere delivers powerful threat detection, incident response, and compliance management for cloud, on-premises, and hybrid environments.

Censys - Censys helps organizations, individuals, and researchers find and monitor every server on the Internet to reduce exposure and improve security.