WowAce

Allows you to create icons, which can be customized greatly by user's input. CiR is more than just the usual cooldown tracker.

Never miss an Brain Freeze, Hot Streak or Missle Barrage proc

Calculates incoming damage avoidance and mitigation

Provides training reminders to help decipher the Blizzard Spell Alerts.

Spell overlay customization and spell state HUD.

SalvationKiller

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.

A frame with a text that gives you the amount absorb left on target, or in TankMode absorbs left on yourself.

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

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

Adds aura indicators to unit frames

oUF element for highlighting debuffs that are dispellable by the player

A Small movable frame that shows who in your party has your Renewing Mist buff

A raid buff tracker

Customizing your buff display

Adds cooldown timers to your trinket procs

Bars showing amount of buffstacks

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

Smooth combat HUD based on ArcHUD2