WowAce

Ignore more than 49 people, autoshared between your alts

Customize the PlayerPowerBarAlt display

Manages the scanning of the auction house in a reliable an efficient manner.

Adds item values to chat messages.

Shows where the equipment of inspected users or yourself is from.

Quest information

Plays amusing sounds whenever you skin a mob

Cartographer_ExtractGas

Announces interrupts in the chat

CraftList

Displays a grid of guild ranks versus permissions.

Bug fix for the Blizzard calendar -- prevents unexpected window closure while editing events

EasyTrack

Expiration

ArenaHistory

Saves contents of your guild bank and sends/receives updates over the addon channel

Replacement of build-in loot frame

Automatic ammo reloading and selection, with warnings.

A library which provide tools for detecting adverse effects on units.

A 'channeling spell'-tracking addon for Affliction Warlocks. Drain Soul, Drain Life/Harvest Life and Malefic Grasp.