WowAce

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

Chat addon, filtering messages and UI changes

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

Give whispers an instant messenger feel.

Shared handling of alternate identity data between addons.

Redirect character errors, system messages and information messages.

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

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

Lightweight Chat Improvements

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

Automate Your GDKP Auctions, Bids, & Payouts

A friendly companion that remembers the chat.

A blizzard group finder replacement

Blocks Chinese Chat

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

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

Addon for creating, storing, and sending chat messages to multiple channels at once. Supports item linking and configurable key binding.

Adds your name to chat messages

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

Automatically leaves the global channels when inside an instance/raid and restores them when exited.