WowAce

Database of item upgrade IDs

Handy notes for your maps

Library providing multi-column tooltips.

Grabs bugs for the bug sack.

Toss those bugs inna sack.

Simple and Advanced combined - Bartender4 ActionBar AddOn

Scan for rare mobs so you can find them and their loot

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

Postal: Enhanced Mailbox support

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

Officially the original source for where things are in the Broken Isles, in HandyNotes

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

Makes the default frames moveable via simple drag and drop

Does stuff for sachmo

Replacement for ActionButton_Show/HideOverlayGlow APIs

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

An intuitive keybindings library.

Tracks rare drops, including companions and mounts

The original source for where things are in Pandaria

Creates and manages secure Action Buttons