WowAce

Notifies you of new calendar event invites and reminds of upcoming events on all characters and realms

Provides accurate, millisecond-level timing.

FuBar_XPerlFu

BigWigs_Debugger

Shows how many epics (and other qualities) you are wearing

Reminds you to resummon your Ghoul

BananaBar2

Replacement for WoW's flash/fade functions.

"Range finder/display for Discipline's Holy Nova"

Shared handling of media data (fonts, sounds, textures, ...) between addons.

I've invented a device that tells you when reactive abilities are available!

DKPmon

Minimalistic group roll frames.

A customizable buff/debuff display replacement for the default Blizzard frames (with right click cancelaura support).

A texture browser for developers and UI modders

Inserts some media that is already present in the game into LibSharedMedia's storage.

Experimental timer library that uses the Animation system as a scheduler.

Standalone LibUnitID, with runtime diagnostic utilities

LDB launcher micro buttons

Adds Debuff Highlighting to oUF.