WowAce

Swiss Army knife for instances, including player tracking, ignore buttons, loot tracking, notes, and more.

Helps you decide which ability to use next according to priority you set

Shows current/dot cast haste values

GirlFriend

Timerbar embeddable library

Creates a broker plugin for all your broker launchers

Reforges stuff

Heal and decurse by clicking on customizable raid/party unit frames

Paints your known blueprints red.

A 'channeling spell'-tracking addon for Affliction Warlocks. Drain Soul, Drain Life/Harvest Life and Malefic Grasp.

Target assistance by automatic rewriting of macros

An extra set of 11x3 buttons, integrated into the default action bar.

AllYouCanEat shows information about the following statistics: beverages, foods, bandage types, potions, elixirs and flasks.

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

Interface-central mount management

item2phpBB

BiGOpt

Displays bars depending on your professions

Make it easy to explain bosses in Raids.

Spawns toasts for looted items, money, and currencies.