WowAce

Embeddable library to track raid/party roster

SRA

Sells all junk in your inventory at once.

Inserts some media into LibSharedMedia's storage.

Inserts additionnal fonts into SharedMediaLib's storage.

Sheppard

AutoMagicly clicks though Daily Quests, and Turns them In.

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

Rebuff yourself with the mousewheel.

Tweak the tradeskill windows

An extension to the default WoW Unit Frames.

A replacement tradeskill window

Changes the look of the default UI

Some handy events that should exist in the default UI

Sphere

A core for your informational plugins to plug into.

A Coordinates Data Broker plugin.

A DPS Data Broker plugin.

Durability Data Broker plugin.

A FPS Data Broker plugin.