Emacs

A text editor… but also way more.

Org-mode

The most versatile plain-text way to keep notes, author documents, and organize information.

Jujutsu

A VCS with a better (Mercurial-like) paradigm

Zellij

A batteries-included Tmux

Fish

A batteries-included, low-setup shell

Guix

A less-supported Nix but in Scheme and with better documentation and (in my opinion) more coherent and considerate design decisions

Notmuch (and notmuch.el)

A dead-simple yet flexible UX for wrangling emails.

Honorable mentions §

Syncthing

Sync files across devices

Zoxide

A cd with memory

Astro

A pain-free web “framework” whose specialty is generating small bundles and static pages; used to build this site

Restic

A dead-simple, fast, versatile, and—above all—reliable backup program.