WowAce

Provides data about all artifacts in the player's possession.

Simple and rich Death Knight rune customizations

Reserve raider tracking for EPGP.

Shows at-a-glance what raid buffs/debuffs you have.

Display combo points for Arcane Blast debuffs

LD50_ap

Shows loot information in item tooltips

A simple addon that warns you if your pet isn't attacking while you're in combat.

Light-weight enhanced casting bars

Seraphim Raid Tracker

Announce which globule to kill during the Yor'sahj the Unsleeping encounter.

Automagically call who should cross over

Keeps track of people who have recently sent you messages.

GridAlert

Adds usable and equipable filters to Baggins

Improved Guild Control Panel

GraphLib

Provides training reminders to help decipher the Blizzard Spell Alerts.

Cartographer_ExtractGas

Notifies you when you get aggro.