WowAce

Detox

Simple, light-weight, LDB-enabled timer that tracks how long you spend in combat

HiveMind

Creates virtual cyphered chat channels over guild addon communication channel.

FuBar_HonorFu

Shows the health of the player's current bodyguard.

Reno is a slash-command that can patch predefined options in a macro to change which abilities will be chosen.

FuBar_CheckStoneFu

Fires events whenever a raid member "fails."

OneChoice tries to help you reduce quest reward choices down to, ideally, one choice.

CharScanner scans Basic Character Data, Talent Specifications, Equipment, PvE/PvP Achievements, PvE Boss Kill Statistics and ...

Automatically invites player from templates.

AceBuffGroups

Monk Brewmaster/WindWalker Priority and Buff/Debuff Tracking Tool

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

Stores a browsable database of spells that mobs cast

Bind spells, items, and macros to keys, without using action buttons

A popup menu containing user-programmable scripts.

Cartographer_QuestObjectives

Need Greed window for EPGP lootdistribution.