WowAce

Keeps track of gold and cash flow across multiple characters

Checklist and notes addon.

RaidGroupNumber

GridStatusIncomingHeals

Echos quest objective completion to your party

Historian

LDB data source for reputation monitoring.

Plays amusing sounds whenever you skin a mob

Debuff Monitor: A Powerful & Configurable Raiding Tool

Pet Battle Lite Frame

Improvements to the standard Blizzard Eclipse bar for balance druids. Use /ebp for the config screen.

FuBar_LootTypeFu

Shows the number of battle resurrections you have and when the next one will become available during a boss encounter.

Captures chatframe Tradeskill Links for later reference in an easy to read format

Shift-clicking on a user name in chat shows a tooltip with their whois information.

Lexan

Displays Currencies as a Data Broker source

Hitman

RBM_AbilityWatch

A library that tells wether a item is a quest item or not (equipped or in bags)