WowAce

PowerPoint goodness for your addon

BetterOutbox

Unit testing framework for World of Warcraft addon development.

User-configurable protection for your inventory. Automatically buys back mistakenly sold items.

Checklist2

Fail display for Recount based on EnsidiaFails filtering options

Destruction Warlock priority module for clcInfo -- Maighurl

Pet Battle Lite Frame

Shows guild and system message of the day only if either one of them has changed since the last login.

Uses TomTom to show target location if target is in party or raid.

Make the unit frame fade if out of range.

Aggro Warning System for Parties and Raids.

Allows raid leaders to view information on raid or guild member equipment information

Shows the spec of people around you in the tooltip.

NCHide

Suppress chat messages when specified items are looted

Makes the message dialog movable

Ranged stats Data Broker plugin.

Notifies you of new calendar event invites and reminds of upcoming events on all characters and realms

ArenaHistory