WowAce

Chat addon, filtering messages and UI changes

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!

Give whispers an instant messenger feel.

A friendly companion that remembers the chat.

Lightweight Chat Improvements

Prat

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

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

Redirect character errors, system messages and information messages.

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!

A blizzard group finder replacement

A Collection of Automations and Interface Tweaks.

Loudmouth

Tracks SendAddonMessage Spam

Creates virtual cyphered chat channels over guild addon communication channel.

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

Toggles WoW to the forground on events.

A collection of useful (guild management) tools and utilities for smarter than average bears.