Hopefully this list will help you get started. Happy hacking!
Vulnerabilities in operating systems
Windows
powershell
batch scripting
Networking
IP Addresses, Subnetting
Protocols: DNS, TCP, UDP, HTTP, SSH
spoofing
Ports
Working with virtual machines
Hypervisors: VMWare Workstation Player, Oracle VM Virtualbox
ISO files
How to run a vm
Linux
Learning the command line
Linux Kernel
Distributions
Bash scripting
Text editors
tmux
Cryptography
hashing
RSA
Security analysis tools
Kali Linux
Wireshark
Nmap
burp suite
Web hacking
javascript vulns
SQL injection
SSRF
Servers + Databases
MariaDB
PHP
Other
TailsOS
Tor
GNU