Tails: Portable, encrypted and secure through the Tor network
Our take
Tails is the tool when you need to leave no trace on the machine you are using: boot it from a USB stick, route everything through Tor, and the session vanishes on shutdown. The amnesia is the whole point and also the catch, since nothing persists unless you set up encrypted storage on purpose, and like all Tor it is slow. Use it for a clean, throwaway anonymous session on hardware you do not own; do not expect it to be your everyday OS.
Listed in
Tails alternatives
Qubes OS Qubes OS: A reasonably secure operating system
Whonix A free, open-source desktop operating system that forces all traffic through Tor, run as two isolated virtual machines.
secureblue secureblue is a security-hardened immutable Linux OS built on Fedora Atomic Desktops. It ships as OCI bootable container images and applies kernel hardening, a hardened memory allocator from GrapheneOS, and a hardened Chromium browser called Trivalent.
Kicksecure Kicksecure is a security-hardened Debian-based Linux distribution that applies a broad set of kernel and userspace hardening settings out of the box, reducing the attack surface without requiring manual configuration. It also serves as the foundation for the Whonix anonymity OS.
Fedora Atomic Desktops Fedora Atomic Desktops (Silverblue, Kinoite, and others) are immutable Fedora variants where the base OS is read-only and updated atomically via rpm-ostree. Applications run as Flatpaks, and rollback to a prior OS image is built in.
NixOS NixOS is a Linux distribution built entirely on the Nix package manager, where the whole system (kernel, packages, services, and configuration) is declared in a single set of files. Upgrades are atomic and fully reproducible rollbacks are a built-in feature.