Various stuff I use and I’m happy with:
Software
Operating system : GNU/Linux (mostly Ubuntu Server, Debian, Gentoo, NixOS)
Text editor : GNU Emacs
Window manager : XMonad, EXWM (Emacs X Window Manager)
File manager : dired, ranger, rox
Terminal emulator : Alacritty
IRC client : Weechat, Circe via Weechat Relay
Web browser : Mozilla Firefox
Internet search: : DuckDuckGo, searx
Email : notmuch
Slideshows : LibreOffice Impress, sent, Reveal.JS, Beamer
Calendar : TrayCalendar
Calculator : Emacs Calc
Version control system : Git, Darcs, RCS
Backups : Borg
Data analysis : R, Jupyter & co.
Multimedia : MPD+ncmpcpp, beets, mpv
Blogging: : Hugo