WowAce

Visual Raid Cooldown Tracking

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

Provides extended aura status settings.

Customizing your buff display

EBB-inspired buff bars with click-to-remove support

Spell overlay customization and spell state HUD.

Bars showing amount of buffstacks

Calculates incoming damage avoidance and mitigation

Adds aura indicators to unit frames

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

Shows a countdown bar for the duration of auras (e.g. HoTs, DoTs)

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

SalvationKiller

Provides training reminders to help decipher the Blizzard Spell Alerts.

oUF element for highlighting debuffs that are dispellable by the player

Filters unimportant Buffs.

Reports in the Default Chat Frame how many people does not have Well Fed effect, and who are they

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...

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

A raid buff tracker