(Web-dev) Odin Project:

https://www.theodinproject.com/paths/foundations/courses/foundations

(General) Codecademy:

https://www.codecademy.com/

(General) freeCodeCamp:

https://www.freecodecamp.org/

(General) Codewars:

https://www.codewars.com/

(Cybersecurity) HackTheBox:

https://www.hackthebox.com/

(Cybersecurity) TryHackMe:

https://tryhackme.com/