WowAce

StarVisuals displays various data visualizations

FuBar_ToFu

Raid Cooldowns

Improved Quest Tracker

Smooth group roll frames

Simple quest item bar.

Keeps track of space left in your bags.

Mapster's Minimap brother

A threat main view module for Recount

Allows you to create icons, which can be customized greatly by user's input. CiR is more than just the usual cooldown tracker.

AltClick an item in your bag to add it a mail, auction, or trade frame, and alt-click to buy a stack if reagents.

FuBar_FuXPFu

Display the global cooldown around your cursor. (+ other stuff)

Keeps track of time played and rested XP across your characters.

Inventory and bank organizer.

Keeps track of current money and all your characters on one realm.

FuBar_ItemBonusesFu

Manages social information with a focus on main-alt associations.

ArenaMaster

Adds options to create customized layouts from within grid.