WowAce

A modular, lightweight and screen-estate saving grid of party/raid unit frames

Kiwi Plates

Custom widgets for AceGUI-3.0 and AceConfigDialog-3.0.

Another HUD addon

Auto repair + shows durability.

Tracks herbs/ore/items that can be broken into component pieces

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

Chat addon, filtering messages and UI changes

Give whispers an instant messenger feel.

A powerful, comprehensive utilty for displaying graphics and information based on buffs, debuffs, and other triggers.

Show what quests have changed

Tracks rare drops, including companions and mounts

Show item levels in the character frame

Drop the cheapest thing you're carrying

Show a texture on demand

Point to quest POIs on your minimap

Watch tooltip updates to announce when you find specific objects

Library of data about what items tier tokens can be turned in for

Show the appearance of an item when you mouse over it

Library to check whether an item is equipable / appropriate for a given class