Parrot Project - Parrot Security OS
Most security folks know about Kali Linux, but there are quite a few alternative security-focused Linux distributions out there.
Parrot is a GNU/Linux distribution based on Debian and focused on Penetration Testing, Digital Forensics, Programming and Privacy protection.
You can download different spins (including an ARM version that can run on the RPi) and try it out for yourself.
A Mastodon instance for info/cyber security-minded people.