Logseq. This is my memory, my work to do, and the easiest way to track it all.

Librewolf - because it is the portal to what's left of the "real" internet.

It's not vi/emacs, because if I can't complete the task with nano, terminal, and Files; then the question becomes should I even be trying to do this?
-- Bonus software Boxes (though not FOSS virtualbox) -- because a VM sandbox of my current distro and others that I want to play with require emulation. Booting off a live USB isn't the same as being able to bounce back and forth between desktop and a sandbox.