Ansible -- I converted my dotfiles install bash script to use Ansible and to also install all my terminal dependencies. Then I started expanding on it to include my entire development box and to provision a bunch of vagrant boxes of different Linux distros so I could test the waters with something other than Ubuntu.

Docker -- Work's been using this now for over a year, and I was a bit of a hold out on it since Docker just seemed like another layer that Ansible + Vagrant was doing a fine job of handling. Once I really dug into how the configurations worked together and set up some of my side projects to use it, it's usefulness started to come together for me.

Otherwise, I keep trying to learn Rust but don't have any projects in mind that would fit with it. I also keep playing with React on the side but haven't gotten very far in my understanding of that ecosystem.