WowAce

A blizzard group finder replacement

Queing of /who and SendWho() queries and a much better interface (see docs), with gurantee to be executed & callback.

Show buffs on nameplates.

Tracks vulnerability debuffs on multiple mobs

Set and manage character notes that are displayed in unit tooltips and /who results.

AutoMagicly clicks though Daily Quests, and Turns them In.

One large inventory.

mount and companion manager

Violation

Keeps track of quests.

DKP system for all guilds in the Banana Republic.

Show item durability and quality in the character frame.

GrindStatus

Visualises healing.

Niagara

Provides access to all Portal and Teleport spells on right click of one button.

Antagonist

Adds mob patrol paths to your map.

Marks the locations of Hallow's End candy buckets on the worldmap and minimap.

CandyBar style cooldown display