WowAce

Building a Better Mailbox

NRT_EPGP

GUI Configuration Library

Spawns toasts for looted items, money, and currencies.

Utilities for pixel perfection, decimal to hex, parsing item strings

A Data Broker display for combat statistics.

Lets you drag UI frames around

Reminds you to Life Tap and Dark Pact

FuBar_FuXPFu

cgCrafty

Fires events whenever a raid member "fails".

Allows for gold tracking across multiple time frames

Displays a grid of guild ranks versus permissions.

Adds Name and Buyout Price sort columns to the auction house.

Displays an alert whenever you loot an item for the first time.

A simple data broker display for current Artifact Power

Cartographer_Herbalism

EUF is an enhance of wow original unit frames, provides hp with both value and %, and optional 3D portrait. Simple and Useful.

Adds Buff/Debuff icons to the grid frame.

Rep2 displays a message, which shows how much reputation you gained, and how much is needed until the next standing.