WowAce

Lists and/or reminds people missing flasks or food buffs at every ready check.

Automatically equip 'Chef's Hat' if the Chef enters the kitchen (Cooking TradeSkill).

Shows optimal target to use various area healing spells

Simple and rich Death Knight rune customizations

Sneakily inspect how much gold your mouseover target has made so far.

Add item levels to Inventorian

FuBar_SpeedFu

Right-click on minimap blips to open a targeting menu (out of combat).

Objective Tracker

Makes grid QuickHealth aware

CatPoints

Data broker for keeping track of your Ankh cooldown.

Target assistance by automatic rewriting of macros

Adds easier gear switching to FuBar.

ChatHighlighter

Lets you drag UI frames around

An attempt at giving a complete overview of Arena battles

A library to help with localization of Archaeology artifacts

Displays oRA3 main tanks.

GCInfo