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.

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

Redirect character errors, system messages and information messages.

Lightweight Chat Improvements

A friendly companion that remembers the chat.

Blocks Chinese Chat

A blizzard group finder replacement

Prat

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

Automate Your GDKP Auctions, Bids, & Payouts

Adds your name to chat messages

A Simple World of Warcraft Spam Filter!

Displays online friends.

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