WowAce

Dynamically atering layout in raid environment (Tanks, Ranged / Melee DPS, Healers)

Nudge

Library to help with querying unit talents.

Quest helping: fetching items to use, that sort of thing.

Interface-central mount management

Lists Pots and Herbs you got on all chars and allows you to specify color coding

Keeps track of honor, PvP statistics, BG Marks, and Arena points.

A library to handle rearrangement of blizzard's frames when bars are added to the sides of the screen.

RaidGroupNumber

BeneCast 10

Combat Alert

Quest information

TrapBar

Provides information about the player's bodyguard.

Privacy2

One-click smart mounting.

Displays a grid of guild ranks versus permissions.

Creates new chats with guild channel functionality

Shows learned recipes of all characters.

Shows a nice Soulstone Monitor.