TryHackMe is an online platform that teaches cyber security through short, gamified real-world labs. We have content for both complete beginners and seasoned hackers, incorporation guides and challenges to cater for different learning styles.
Hack The Box is an online platform allowing you to test your penetration testing skills and exchange ideas and methodologies with other people having similar interests. It contains several challenges that are constantly updated.
picoCTF is a free computer security education program with original content built on a capture-the-flag framework created by security and privacy experts at Carnegie Mellon University.