WowAce

A library to help with localization of item types and subtypes.

Libra

LibItemInfo-1.0

Library that tracks incoming heals

Library providing mappings between trade skill recipes, spells and created items

A library to provide a markup syntax

A library to provide unit-oriented tags to LibDogTag-3.0

Communicates with guild members for their positions on the world map

AddOn development framework

Additional information about player spells.

Provides one or many informational windows with optional interactive widgets.

A library to provide a clean dropdown menu interface.

Static library of wow map data

Good old LibTourist-3.0 for WoW WotLK Classic

Fires events whenever a raid member "fails."

A library to handle rearrangement of blizzard's frames when bars are added to the sides of the screen.

Good old LibTourist-3.0 for WoW Classic Era

Database of Diminishing return categories and general data

A library to provide tools for formatting money and time.

A library to provide mobIDs for bosses.