WowAce

Shows current/dot cast haste values

Hourglass

A Data Broker add-on for quickly switching your specialization with gear set and loot specialization.

Loot management tool

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

Enable/Disable addons for your character in game

Recap

Displays the time until the next battle and more.

Displays info about who rolled Need/Greed/Pass on items that are currently rolled for

Saves contents of your guild bank and sends/receives updates over the addon channel

Ghost: Pulse

ChatAssist2

GirlFriend

Database of important locations for HandyNotes

Stable

Calculates optimal reforging for given weights/caps.

Percent

MessageEvent

KivinSpamGuard

PiraPlex