WowAce

Add-on that shows in a unit tooltip window a number of killed mobs of the same kind

Adds TargetIcon status to Grid2 (player / player-target).

Adds support for LibFilter to Baggins

oUF_HolySmurf

oUF Layout

LDB display of the players current damage percent modifier

Skills plugin for any DataBroker display.

VendorSearch adds search features when buying items from any vendor

RepWatch

Uses TomTom to show target location if target is in party or raid.

Shows on the minimap where to fetch Finklestein's reagents

A collection management library similar to .NET's System.Linq

Toolbox-1.0

Adds filtering based on your known professions.

SEasyRotation

Automagically call who should cross over

HealGraph

Makes the message dialog movable

User-configurable protection for your inventory. Automatically buys back mistakenly sold items.

Provides a virtual keyboard of extended-ASCII and Unicode characters which can be inserted into text areas.