I guess these are so obvious no one mentioned them, but: ssh, git, zsh, bash, curl, wget, gpg, gzip, xz, btrfs, qemu, pv, tar, diff, comm, column, sort, uniq, s

I guess these are so obvious no one mentioned them, but: ssh, git, zsh, bash, curl, wget, gpg, gzip, xz, btrfs, qemu, pv, tar, diff, comm, column, sort, uniq, sed, bc, tr, od, xxd, tcpdump, tshark, ping, nmap, ip, iw, xdotool, xrdb, grep, pgrep, pkill, lsof, inotifywait, journalctl, systemctl, convert, ed, and probably countless more I'm taking too much for granted to remember.