WowAce

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

Automatically switches Profiles of addons when changing spec

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

Provides accurate, millisecond-level timing.

Frame layout manager for side panels.

Relegation

Avion2

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

SuccessionDKP

Ich bin ein Paparazzi.

A library to provide a way to easily create controls for Blizzard's options system

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

Aggro notification library.

oUF_HolySmurf

GCInfo

Minimalistic LDB-based friends display

Displays your soulshards in better way.

Guide Handler UI.

Bang!_Libram_Swap

Locks the chat window tabs to prevent accidental undocking via mouse drag