Qubes OS

Qubes is certainly a great addition to this list. Keep in mind that its “live” version is no longer supported. You can still run it from USB drives or external drives, but you will need to “install” it first The OS on these disks.

It uses so-called virtualization. In fact, it is isolation/separation/compartmentalization for various tasks. This includes activities such as browsing the web, editing documents on social media, banking, etc.

Essentially, this ensures that even if your document viewing/editing or some other aspect is compromised, other aspects and the system will still remain secure.

Disposable virtual machines are another thing that fascinated me when I first heard about them. When you are going to do something questionable or maybe just suspicious, this will come in handy. For example, when you open an attachment to an email message, visit a potentially dangerous site, etc. As soon as the task is completed, the one-time virtual machine is automatically deleted, preventing any potential threats from being stored in the system.

It also includes TemplateVMs, which are pre-configured virtual machines that can be used to create new APPVMS.  Therefore, if you are new to virtual machines, you can still create these virtual machines with pre-configured parameters and configurations.

I like its “SecureBoot" feature. It checks the integrity of the boot process and prevents any unauthorized changes to the system.

Oh, Edward Snowden is also a Qubes supporter.