Websites

Rawsec's CyberSecurity Inventory

is an inventory of tools and resources about CyberSecurity that aims to help people to find everything related to CyberSecurity.

Rawsec's blog

is a blog talking about Linux and security but also where Rawsec CTF team posts challenge write-ups.

Ruby Cheatsheet

is a lovely Ruby language cheatsheet.

The Hacking Trove

is the hacker technical cheat sheet and it can definitely help you during your penetration test, technical security audit, PWK/OSCP Lab or exam, CTF, challenge, training, etc. by providing cheat sheets, tools, examples, references, etc.