Adafruit

You'll need to convert Adafruit's parts library. Original Eagle: https://github.com/adafruit/Adafruit-Eagle-Library

Sparkun

You'll need to convert Adafruit's parts library. Original Eagle: https://github.com/sparkfun/SparkFun-Eagle-Library

Halley

A single component library with the Arduino Pro Mini It used to be here: http://halley.cc/paste/Halley.lbr but that's no more.

Conversion to Kicad

The libraries, converted to Kicad can be found here: https://docs.google.com/folder/d/0B6eYEJ4QzAmBS0paSks4ckowYjA/edit