I am in no way affiliated with any of the below sites or organisations, these are just things ive found and use.
kali.org – Website for Kali Linux includes documentation and OS Downloads
CyberChef – Useful for decoding ciphers
crackstation.net – Website for cracking password hashes
tryhackme.com – You can participate in CTF Games
GTFOBins – List of Unix binaries, good for Privesc
Boxentriq – A link to the Boxentriq Cipher identifier
Reverse Shell Cheat Sheet – On the pentest monkey website, a list of reverse shell commands
Dion Training – A great trainer for IT Security, I’ve used Jasons courses to prep for exams
Defcon Youtube – Great Channel, you can watch their previous talks from DEFCON on youtube!
IntelliJ – My favourite IDE for python from Jetbrains, you can download the free community edition
Anaconda – This is the IDE I use for anything related to neural networks using the spyder application
Goorm – A cloud based IDE, they have an option specifically for MySQL which is good for practicing MySQL.
PHP Reverse Shell – Made by Pentest Monkey, my go to when i need a PHP Reverse shell
LinPEAS – This is like magic, run it on a linux machine and it will give so many ideas from privilege escalation.
Upgrading Shells – A good reference guide for beginners on how to upgrade shells with simple, short commands, i still use what i learned on here.