WowAce

Collects Herbs, Mines, Gas Clouds, Archaeology, Treasure and Fishing locations and adds them to the worldmap and minimap

Database of item upgrade IDs

Collects Herbs, Mines, Gas Clouds, Archaeology, Treasure and Fishing locations and adds them to the worldmap and minimap

A skinning engine for button-based add-ons.

Show item levels in the character frame

Replacement for ActionButton_Show/HideOverlayGlow APIs

A library to help with localization of the output of UnitCreatureType.

An intuitive keybindings library.

Creates and manages secure Action Buttons

Library to check whether an item is equipable / appropriate for a given class

Allows you to view all items from all your characters on the same account, when-ever and where-ever you want.

Arena unit frames

The original source for where things are in Pandaria

Tracks Raid/Instance/World Boss lockouts for all your characters, daily/weekly quests, currencies, trade cooldowns, and more!

A library to help with localization of bosses.

Another HUD addon

A library to help with localization of races.

Shared handling of alternate identity data between addons.

Adds a Button to the Worldmap which toggle Handynotes

Library of compressed itemid sets.