- neomutt - khard - khal - irssi - mcabber
Some of my favorites for personal (non-server) use are zsh, tmux, irssi, youtube-dl, ranger, vim, mpd+ncpcpp, redshift, git, python, and all the usual core utils.
Don't forget to use as many custom aliases, themes, and functions as possible if you're going to stick with it. I even use many one-character aliases for common things, e.g. 'p' for python.
youtube-dl and python are also nice.
Newsboat, a great RSS feed reader.