WowAce

AutoMagicly clicks though Daily Quests, and Turns them In.

tracks and share quests between your party

Deathknight Rune Display

Keeps track of space left in your bags.

Configure triggers to send messages to your raid team such as timers, rotations, and health/power based triggers. Raid smarter not harder.

Reports in raid chat whenever a raid member "fails." /EnsidiaFails to configure.

LDB display of currencies, gold totals and session / daily / weekly statistics for all characters on a server.

A core for your informational plugins to plug into.

Violation

Healer gear benchmark

Addon to provide a much nicer map

TomTom CrazyArrow pointing to the targeted group member

Henge

Attach diminishing return icons to unit frames.

A data broker display, that shows one block per plugin.

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

Necronomicon2

Show where the chests are for Withered Army Training

HUD that you can tweak the way you want.

Displays online guild mates.