WowAce

Track all threat redirection ability transfers and cooldowns (Misdirection and Tricks of the Trade).

Keeps track of current money and all your characters on one realm.

Says random things in chat when casting any spell or ability. Type "/ss help" for the user's manual.

Some handy events that should exist in the default UI

Keeps track of quests.

Tooltip of awesomeness. Moo. It'll graze your pasture.

Mining data for Ackis Recipe List.

Adds World Quests to the quest list

A library to help with localization of Zones.

Add-on that shows in a unit tooltip window a number of killed mobs of the same kind

Adds your name to chat messages

Displays Instance Maps

Simple right click casting.

Tracks, transmits and displays the cooldowns of your raid.

Adds unreal tournament style sounds to PvP encounters.

Visualises healing.

Tracks the HoTs you cast.

Checks your gear before bosses and yells at you if you're an idiot

A Simple World of Warcraft Spam Filter!

Provides the /in command for delayed execution.