WowAce

Scan for rare mobs so you can find them and their loot

Tracks Raid/Instance/World Boss lockouts for all your characters, daily/weekly quests, currencies, trade cooldowns, and more!

Chat addon, filtering messages and UI changes

Give whispers an instant messenger feel.

Shared handling of alternate identity data between addons.

Enables multi-line/unlimited-length pasting of text or commands into WoW

Watches your chat, flagging missplled words, and offering correctly spelled suggestions.

Lightweight Chat Improvements

Redirect character errors, system messages and information messages.

A friendly companion that remembers the chat.

Set and manage character notes that are displayed in unit tooltips and /who results.

Blocks Chinese Chat

A blizzard group finder replacement

A simple slash-command-based addon for querying item information from the Blizzard servers via ItemIDs and SpellIDs.

Automate Your GDKP Auctions, Bids, & Payouts

Prat

Manages social information with a focus on main-alt associations.

Configure triggers to send messages to your raid team such as timers, rotations, and health/power based triggers. Raid smarter not harder.

A Simple World of Warcraft Spam Filter!

Save and send chat messages to many channels. Allows quick item and profession linking within your messages.