ZoomEye - Network mapping service
Shodan - Shodan is the world's first search engine for Internet-connected devices.
Armitage - Armitage makes penetration testing easy by adding a GUI to the Metasploit framework
Vega - Subgraph Vega | Free and Open Source Web Application Vulnerability and Security Scanner
IVRE - Network recon framework, including a web interface to browse Nmap scan results.
w3af - w3af is a Web Application Attack and Audit Framework