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.

A friendly companion that remembers the chat.

Lightweight Chat Improvements

Shared handling of alternate identity data between addons.

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

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

Prat

Redirect character errors, system messages and information messages.

A blizzard group finder replacement

Displays online friends.

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

Displays online guild mates.

A Simple World of Warcraft Spam Filter!

A Collection of Automations and Interface Tweaks.

Loudmouth

Mutes various chat related annoyances while in capital cities and instances.

Tracks SendAddonMessage Spam