1. Slack. Pretty good chat app for dev companies, I use it to prevent people standing next to my desk 40 times a day.

2. Unit testing tools, especially when fully automated using a git master branch hook, something like codeship/jenkins, and a deployment service.

3. Jetbrains IDEs. I love Vim, but Jetbrains makes theming, autocompleting & code style checks with mixed templating languages a breeze.

4. Urxvt terminal. It's a bit of work at the start, but so extremely fast and customizable.

5. Cinnamon or i3. Not really dev tools, but both make it easy to organize many windows.

6. A smart production bug logger. I tend to use Bugsnag, Rollbar or Sentry.

7. A good coffee machine. Preferably some high pressure espresso maker which costs more than the CEO's car, using organic fairtrade hipster beans with a picture of a laughing south american farmer. And don't you dare fuck it up with sugar.

8. Some high quality bars of chocolate. Not to consume yourself, but to offer to coworkers while they wait for you to fix a broken deploy. The importance of office politics is not to be underestimated.