WowAce

Display the global cooldown around your cursor. (+ other stuff)

SanityItemCache

Add-on that shows in a unit tooltip window a number of killed mobs of the same kind

Cartographer_Treasure

StatStain

Visual loot monitor

Provides a quick display for the LFG Call to Arms

Allows customisation of login/logout system messages.

Adds four icon indicators to Grid (top, bottom, left and right).

Heads Up Display with Player and Target Info

Tracks interrupts

item2phpBB

Insanity resource tracker for shadow priests.

Tracks whispers and conversations

StitchUI

Assister

Automatic Refilling of User Defined Items

Allows the user to customize the the tooltip with lua-scripts

mHud

Tells you who bought your auctions.