WowAce

Helps you decide which ability to use next according to priority you set

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

A library to track nameplates.

eeShards

Tells you which blob to kill at the Yor'sahj encounter in Dragon Soul.

Loot Distribution System

Good looking, smoothy and helpful nameplates

Cartographer_Routes

Tracks skill and tradeskill costs and progressions, as well as trainer locations.

AutoMagicly clicks though Daily Quests, and Turns them In.

Check the consumable usage of your raid

Fancy up the ExtraActionButton frame

A library to get currencies' related information

Insanity resource tracker for shadow priests.

AspectsBar

FuBar_MicroMenuFu

A Data Broker display for combat statistics.

Improved Quest Tracker

Resizes some default UI frames (GuildUI, LootFrame, RaidInfo, TradeSkillUI and TrainerUI) to show more lines

Tracks interrupts