Resources

CTF sites (Free and Paid)

• Hacker 101
• Try Hack Me
• Zaratec
• Vuln Hub
• Hack The Box Academy
• Hack The Box Labs
• pwn college
• Google CTF
• TCM Security
• Pico CTF
• PortSwigger Web Security Academy
• Vuln Lab

Other CTF-ish Hacker-y things

Bug Bounty

• Bug Crowd

Hacking Practice Sites

• OWASP mutillidae-ii
• Hack This Site

More Challenges and Learning

• Sans Holiday Hack
• Over The Wire
• Hack Tricks
• Leetcode
• Codewars
• Linux Journey
• Untrusted Game

Reference Sheets and Textbooks (FREE)

• My Reference Sheet Site