Devel

Essential module for developers. Should be disabled in production environments.

Search Krumo

Use search Krumo Search to extend Devel to get a search box for your dpm(). A new search box appears above all krumo prints.

If you use sdpm(), you get a really nice feature that lets you copy the full path of the variable, "for the lazy programmers"...

Metatag

From the Drupal module page, "The Metatag module allows you to automatically provide structured metadata, aka "meta tags", about a website."

Focal Point

Sponsored by NBCUniversal, the focal point module seems to have been inspired by the image field focus module