WowAce

Tracks rare drops, including companions and mounts

Chat addon, filtering messages and UI changes

The original source for where things are in Pandaria

A Replacement for standard UIDropDownMenu

Grabs bugs for the bug sack.

Makes the default frames moveable via simple drag and drop

Modular casting bar.

Afflictions display and cleaning for solo, group and raid with advanced filtering and priority system.

Arena unit frames

Library providing multi-column tooltips.

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

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

A library for transmitting and receiving latency information of players.

A modular, lightweight and screen-estate saving grid of party/raid unit frames

Show item levels in the character frame

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

A library allowing for easy creation of graphs

Officially the original source of knowledge of where things are in Draenor during Warlords, in HandyNotes

Keeps track of group members and keeps an up-to-date cache of their specialization and talents.

A skinning engine for button-based add-ons.