Emacs - I learned Vim last year and was forever changed by modal editing and using only the keyboard. I was interested in Emacs for a while but couldn't move past the shortcuts. That led to evil-mode and Doom Emacs, which I've since been using. These are some of my favorite new tools, and I take a lot of joy finding new thinks to optimize in my config files.

Bash - This is still a work in progress, but I've enjoyed the ease Bash provides for scripting, compared to doing the same thing in Node or Python.

Unix - In the last few months, I've started familiarizing myself with different commands, such as sed, grep and awk, to navigate around the command line and edit files. I'm hoping to get better in 2019.