WowAce

A library that tells wether a item is a quest item or not (equipped or in bags)

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

TipHookerLib

Note + rep tracking for players, with guild data sharing.

Diplomat

A small datatext for ElvUI-using Shamans that gives them accurate info about their Reincarnation cooldown

A boss encounter engine used by other add-ons

Improvements to the standard Blizzard Eclipse bar for balance druids. Use /ebp for the config screen.

For Developers (of Addons which uses LibWho-2.0): show queues and queries in realtime

A helper addon for the achievements "Let It Snow", "Fistful of Love", "Shake Your Bunny-Maker", "Check Your Head", and "Turkey Lurkey"

Handles the assignment, coordination, and announcement of many parts of the Lich King encounter in Icecrown Citadel.

Track any items you want in a tooltip

Historian

BigTrouble

Provides quick notification (sound and visual) of your tanking status of your current target. Meant for tanking.

Displays the time until the next battle and more.

TunnelVision

Adds Friend and Guild options to the context menu of player units.

A library to return spell duration and debuff type of a spellID.

Group interrupt cooldown tracking.