WowAce

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

XArt

Waitlist addon with EPGP Mass Award hooking.

ElectrofluxTextronator

Shows a window displaying any raid member below 10,000 health during the Chimaeron encounter.

DebuffEnough

Notifies you of experience gains

A popup menu containing user-programmable scripts.

Displays information about the current zone on the World Map

cgCrafty

LibDataBroker plugin showing some random XP related data

Protractor

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

Filters AFK and DND messages after you've seen them once.

Automatically sells low quality gray items and selected white items to the vendor.

Warns you with sounds when you gain different shaman spells.

Adds a button to the quest completion interface which allows you to auto equips selected quest Item after completion

Keeps track of honor, PvP statistics, BG Marks, and Arena points.

Right-click on minimap blips to open a targeting menu (out of combat).

Tooltip of socials button will now show which friends are online