WowAce

Paints your known blueprints red.

Lightweight time display, with micro menu and memory usage tooltip.

Locks the chat window tabs to prevent accidental undocking via mouse drag

TrickOrTreat

Nostalgia

Automatically calls ForecQuit() right before you are AFK-disconnected to quit wow instead of going to the character selection...

Customizable text display of character's power.

A texture browser for developers and UI modders

Joins the LFG channel automatically.

We be rendering, mon!

MouseLook

SpellEventsLib

An herb and ore gathering add-on with a focus on ease-of-use.

Continuation of Shadowed Unit Frames

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

"Your quest log is full". How many quests do you have in your log?

MarySue

ForceEnchant

Shows the number of battle resurrections you have and when the next one will become available during a boss encounter.

FuBar_OmenFu