Pen Testing Standard: http://www.pentest-standard.org/index.php/Main_Page
OSINT Framework: https://osintframework.com/
OWASP Top Ten 2017 Project: https://www.owasp.org/index.php/Category:OWASP_Top_Ten_2017_Project
Nmap - The Network Mapper: https://nmap.org/
PuTTY - SSH and Telnet Client: https://putty.org/
Metasploit - Pentesting Framework: https://www.metasploit.com/