WowAce

Raid Frames using the oUF framework.

A blizzard group finder replacement

Provides access to all Portal and Teleport spells on right click of one button.

tracks and share quests between your party

Marks the locations of Midsummer Fire Festival bonfires on the worldmap and minimap.

XRS

Create panels for customizing your UI, sucessor to eePanels

Automatically enables or disables combat logging based on location.

Bulk mail sending made really easy

Bayi's Extended Questlog

Queing of /who and SendWho() queries and a much better interface (see docs), with gurantee to be executed & callback.

A library to provide a markup syntax

mount and companion manager

Adirelle's unit frames, based on haste's oUF.

Auto repair + shows durability.

Incubator

Reduces interface tedium by doing the little things for you.

Shows you the radius of your totems.

Cleans up minimap buttons and makes them accessible through a pop out menu!

ArcHUD2