WowAce

Keeps an eye on someone's distance from you, and alerts you if they get too far.

Counts stacked lifeblooms and uses progressive colors to indicate the active number of HOTs.

Mirror

Automatically switches Profiles of addons when changing spec

Displays how much total honor you have from all sources.

Adds cooldown timers to your trinket procs

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

A library to provide coloring tools.

Raid cooldown assignments for healers

CraftBotFu

Shows more recipies in the profession window.

Tracksw

A lib to manage action bar and timers

Adds Buff/Debuff icons to the grid frame.

Gnomish math at its best!

Adds an inobtrusive circular castbar around the mousecursor, handy for Clique users

Melee stats Data Broker plugin.

Allows you to loot BoP items without prompting when not in a group or raid

Send Messages encoded with the hexadecimal system

A library to try to guess a level of a player.