WowAce

Tracks whispers and conversations

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

Cryolysis

Shows your standings with the factions.

Automatic ammo reloading and selection, with warnings.

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

Replacement for the default minimap.

Library to help with querying unit talents.

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

DebuffEnough

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

Hotkey interface for spells, macros, other clickables.

Merchant, gossip and taxi tweaking module for TweakHub.

ItemRackFu

Sorts the Wardrobe

Library providing mouse-click support for LibQTip-1.0.

A death track window for Recount

Displays a reliable cooldown timer for the Shaman Ascendance ability

UnitActionBars2

Replacement of build-in loot frame