Hack The Box - An online platform to test and advance your skills in penetration testing and cyber security.

TryHackMe - TryHackMe is an online platform for learning and teaching cyber security, all through your browser.

VulnHub - VulnHub provides materials allowing anyone to gain practical hands-on experience with digital security, computer applications and network administration tasks.

PwnTillDawn Online Battlefield - PwnTillDawn Online Battlefield is an online platform that allows you to learn and improve your pentesting and other cybersecurity assessments skills.

PentesterLab - Learn all about web hacking through online courses spanning the basics to advanced vulnerabilities

HackThisSite - Hack This Site is a legal free training ground for users to test and expand their hacking skills.