WowAce

Utility library with shared functions and data for various addons by NeoTron.

Considers an item against all the items you have to determine whether or not it is an upgrade

A Library for stat conversion, calculation and summarization.

Scans your Equipment for cumulative item bonuses and sums them up.

AnyFont

RoleCall allows you to easily see the talent specs and roles of everyone in your group.

Tracks your keystones

Add-on that allows you to setup and quickly switch between different profiles of your action bars

Provides information of tradeskill and crafting materials that are in the banks and bags of your characters.

EnchantList

Announces Mage Spells in chat.

Library supporting plug in filters.

lugMD

Aspect checker addon for Hunters.

Reorients the camera to be behind the character after a charge.

Don't underestimate your little critters!

DeuceCommander

Shared handling of media data (fonts, sounds, textures, ...) between addons.

ItemValue

Highly-configurable shield / absorb tracker.