Nmap
Description: Nmap is an open source network discovery and security auditing tool. It is used to discover hosts and services on a network and to detect potential vulnerabilities.
Type: software
Pricing: Free
Quora
Description: Quora is a popular question-and-answer website where users can post questions and get answers from a community of experts and other knowledgeable people. Its focus is on gaining and sharing knowledge.
Type: software