WowAce

Profiler of the Lords of the Zodiac guild.

Provides database of quest giving npcs/mobs/objects for display on the World Map/Minimap

Shows class colors on player nameplates and names

Displays the locations of Garrison music scrolls.

Shared handling of media data (fonts, sounds, textures, ...) between addons.

Dedicated to Lazybones of EU Khadgar who had the original idea as he can't find a damn thing in his bags. You're a great guy...

Adds a couple of graph displays to Skada.

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

Provides information of tradeskill and crafting materials that are in the banks and bags of your characters.

ClosetGnome_Mount

opens/closes all bags when at merchant (instead of only the backpack)

Reno is a slash-command that can patch predefined options in a macro to change which actions will be chosen.

Helps you automate selling stuff.

Reorients the camera to be behind the character after a charge.

FuBar_CRDelayFu

Depot

Show what quests have changed

Leveling guides for trade skill professions.

Used to visualize and change values of variables/variable-trees in game

Timerbar embeddable library