WowAce

Keeps track of important de-/buffs in a splash screen

Test whether the player can really dispell a buff or debuff, given its talents.

Allows combined aura detection. motw + gotw, all 4 mage int buffs, etc. in one status.

Adds an additional spell alert if you have more than one charge of a buff that is normally tracked by the in game spell alert...

Adds aura indicators to unit frames

Visual Raid Cooldown Tracking

Audible Alerts for self-gain, self-lost, any-gain, all-lost of statuses.

Provides extended aura status settings.

A customizable buff/debuff display replacement for the default Blizzard frames (with right click cancelaura support).

SalvationKiller

rSelfCast

Assistance for the Ra-den encounter. (Unstable Vita order, ball kill order)

Holy Power, Shadow Orbs, Rogue Combo Points and Monk Chi.

Calculates incoming damage avoidance and mitigation

Desesperated announcing to clearly show the skillings of act inplay.

WeaponRebuff

Spell overlay customization and spell state HUD.

NBuffBars

Tracks spiritual innervation on Garajal

Shows a frame to track your Pyrite debuff on Flame Leviathan and it's trash. Completely based on MalygosStacks by Nebula.