WowAce

Keeps track of space left in your bags.

Cancellation

Transcendence Monitor for Monks

Database of FlightMaster locations for HandyNotes

mHud

Rep2 displays a message, which shows how much reputation you gained, and how much is needed until the next standing.

ItemBonusLib

Estimated time until current target will die.

Provides database of quest giving npcs/mobs/objects for display on the World Map/Minimap

Tracks SendAddonMessage Spam

Shows the health of the player's current bodyguard.

NBuffBars

Allows you to create icons, which can be customized greatly by user's input. CiR is more than just the usual cooldown tracker.

An auction house AddOn to make the life of each fence easier.

Various libraries based on LCD4Linux, offering users lower-level UI customizations.

Fires events whenever a raid member "fails".

Smart raid loot and DKP tracker with automated standby and learning

Monk Brewmaster/WindWalker Priority and Buff/Debuff Tracking Tool

Client for MagicDKP which handles standby calls and bidding on items.

Shows your standings with the factions.