This guide from our friends at UCLA is probably the best way to get started, but here are some tools that we personally use.

Steganography

• RX-SSTV (anything beep related)
• Digital Invisible Ink Toolkit (relies on Java)

Cryptography

• Cryptii
• DCode (for niche bases)
• rapidtables (for common bases)
• CyberChef (bruteforce)

Forensics

• FTK Imager (or Autopsy)
• 7-Zip

VMs

• Apache Guacamole <- not the most reliable, but can help if you are on a Chromebook
• VirtualBox + Parrot OS

Network

• Wireshark (for Packet Tracer)
• Proton/SoftEther VPN

Reverse Engineering

• Ghidra

For a list that's constantly updated, check this list out.