I use emacs, which might be thought of as a thermonuclear word processor. It was created by Richard Stallman; enough said. It is written in Lisp, which is the only computer language that is beautiful.
Neal Stephenson - In the Beginning was the Command Line
For most of my writing and programming I use the Emacs editor.
I maintain the org-fc package that turns Org Mode into a spaced repetition system.
Org Zettelkasten collects some code I use to manage and navigate a collection of .org files like the one this website is based on.