WowAce

RBM_Sunwell

With Mists of Pandaria Blizzard publish all characters from an account unless you disable that 'feature'. This addon warns you.

Cartographer_Data

Gives equipped and overall iLvl to indicate the quality of a character's gear.

Envenomous

Unsolicited

Auto sizes frame layout depending on group/raid size

MalygosHelper

Addon channel transfer statistics for any DataBroker display.

Nostalgia

oUF Layout

Enigma

Enhelper

A library to manage snappy dragging & sticking of frames across multiple mods.

MarySue

Adds filtering based on your known professions.

Blocks all whispers except from people in your guild and friends list.

Check for flask/food buffs

Tracks if the target does NOT have the tracked DOT.

LDB display of the players current damage percent modifier