Here's a list of things I've automated at work:

• Backups: As we're using MySQL databases and Percona Xtrabackup to backup these, I've created some Python scripts to automate the backup/storage steps: github.com/deviantony/xtrabackup-scripts
• Backup validation: How to check that the backup archive we created is valid? Well, I've created a tool that leverages Docker to create ephemeral containers in which a backup restoration can occur: github.com/deviantony/valigator
• Bootstrap projects: I've played with Yeoman (yeoman.io) to create a Puppet module generator (github.com/deviantony/yeoman-puppet) and a Angular-Bootstrap generator (github.com/deviantony/yeoman-angular-ngbp)
• Created a set of bash libraries
• Automation of the server provisioning / configuration process using Puppet (puppetlabs.com) and Foreman (theforeman.org), this allowed us to easily and quickly deploy new servers
• Also a lot of processes manually done before in the company, replaced by bash scripts or command lines triggered/scheduled by Rundeck (rundeck.org)

@deviantony has given the best answer possible. My answer would be:

@extend (deviantony)

Ansible -- instead of Puppet; Python -- instead of Bash (however, I still have some low-level stuff in bash) Tonnes of dotfiles. Because, hey, that's what programmers strive to be: more lazy.

And lastly, my favorite: an automate for Ansible so I can deploy bare-metal machines with PXE Boot. This one took me 2 months to create, but was completely worth it! I'll be open-sourcing it soon! :)