This whitepaper touches on various scanning tools and how to use them. It gives an overview of hping, scapy, unicornscan, nmap, and nessus.
You can download it from the following link: https://packetstormsecurity.com/files/download/112886/Scanning22v3.pdf
Source: https://packetstormsecurity.com/files/112886/Scanning-Tools.html