WowAce

A library which provide tools for detecting adverse effects on units.

Automatically switches Profiles of addons when changing spec

Visual interrupt monitor

Reports the total threat on a mob at the end of combat.

PowerPoint goodness for your addon

A library to provide extended information regarding player spell action/macro cast requirements.

Adds an additional spell alert if you have more than one charge of a buff that is normally tracked by the in game spell alert...

Allows custom Combat Log filtering

Allows you to create icons, which can be customized greatly by user's input. CiR is more than just the usual cooldown tracker.

Library to aid in the classification of Mounts

Makes most default frames movable (mailbox, achievements window etc.)

StarVisuals displays various data visualizations

Continuation of Shadowed Unit Frames

A Library for stat conversion, calculation and summarization.

Displays Currencies as a Data Broker source

Resizes Blizzard raid frames, and adds additional options.

Database of reforging IDs

Shows what stat was reforged in item tooltips.

Allows movement and scaling of class-specific resource displays

Vengeance module for Broker displays.