WowAce

A library that handles the basics of "window" style frames

Utility library with shared functions and data for various addons by NeoTron.

Queing of /who and SendWho() queries and a much better interface (see docs), with gurantee to be executed & callback.

StatLogicLib

Library handling communcation for Magic* addons

Simple library that handles multiple levels of logging.

A library to help with localization of Zones.

TabletLib

A library to help with localization of talent trees.

A library to provide a clean dropdown menu interface.

Some handy events that should exist in the default UI

Adds predicted lists for spells while the user types

A library to get currencies' related information

Embeddable chat throttling library with traffic shaping and priorities

Threat-2.0

A library to help with localization of classes.

IncomingHealsLib

Library to help with querying unit talents.

A library to handle rearrangement of blizzard's frames when bars are added to the sides of the screen.

Library supporting plug in filters.