Shodan

Web debugging proxy to log all HTTP/HTTPS traffic between your computer and the internet

Command line tool and library for transferring data with URLs for all protocols

Network-wide software for blocking ads and tracking and managing DNS traffic

Open-source network scanner that enables researchers to easily perform Internet-wide surveys

Combined ping and traceroute tool for diagnosing network latency and packet loss

Tool for scanning large batches of domains for various security and web stats