WowAce

Creates new chats with guild channel functionality

Paparazzi

Replacement for the default nameplates.

Warns you with sounds when you gain different shaman spells.

SinkLib

Evaluates your gear

Reverse Engineering will drill down and search your tradeskills for their elements

SwapMagic

GetInLine

LDB data source displaying rested XP for whole account

FuBar_TinyPadFu

Responds to DBM version checks, so that you don't have to.

Adds pipes which can control arbitary other statuses (like toggle status on key or "in combat"-state).

Enable/Disable addons for your character in game

Compact scrolling vendor frame

Cartographer_ExtractGas

A Small movable frame that shows who in your party has your Renewing Mist buff

Adds options to create customized layouts from within grid.

Shows a circle on the minimap to indicate spell range

Embeddable library to track raid/party roster