WowAce

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

Improved Questing Experience

Enhances the default AddOns list.

DKP system for all guilds in the Banana Republic.

Shows mana usage as a percentage in a spells tooltip.

Modular and lightweight party/raid frames.

A simple slash-command-based addon for querying item information from the Blizzard servers via ItemIDs and SpellIDs.

Shows skills in a tooltip and allows them to be used.

Helper functions used by my addons, feel free to use them in your addon too

Shows simple Buttons for your Cooldowns :)

A core for your informational plugins to plug into.

An auction house AddOn to make the life of each fence easier.

cyCircled

Role playing AddOn that shows extra information about characters as entered by the player.

A Friend-Enemy-Unit-Frame for battlegrounds.

A library to help with localization of Zones.

Mutes various chat related annoyances while in capital cities and instances.

Keeps track of space left in your bags.

A library to provide mobIDs for bosses.

ArcHUD2