WowAce

Reminds you if your flask/elixir and/or Augmentation Rune and/orfood buff is about to expire or has expired

WF3sec

Privacy2

Adds two icon indicators to each corner (total: 8 icon indicators).

Simple library that handles multiple levels of logging.

Group interrupt cooldown tracking.

Shows the minimum durability of equipped items on the stats frame.

NielasAran

Simple, nice-looking power bar addon for all classes.

Tracks profession specific cooldowns and items across all your characters

Collect data about you myth+ challenges

Quest helping: fetching items to use, that sort of thing.

Displays friend notes in unit tooltips, at logon, and in /who results.

Handles the assignment, coordination, and announcement of many parts of the Lich King encounter in Icecrown Citadel.

Announces ooze kill instructions during the Yor'sajh encounter in Dragon Soul. Highly customizable with numerous helpful feat...

Shows current/dot cast haste values

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

Retooled Professions

TwiCo

LDB data source for reputation monitoring.