WowAce

Splut

TrickOrTreat

A Data Broker plugin to show AddOn memory usage.

Enables cooldown notification between players and allows party members access to each-others spell books.

tekProber

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

A simple addon that warns you if your pet isn't attacking while you're in combat.

CraftList

Customize the appearance of the chat bubbles.

Fancy up the PlayerPowerBarAlt frame

Communicates with guild members for their positions on the world map

A Perl layout with oUF.

Square Minimap and more

Show optimal path for artifact leveling

Allows for easy congratulating when someone earns an achievement.

FuBar_MiniClockFu

Target assistance by automatic rewriting of macros

Dynamically atering layout in raid environment (Tanks, Ranged / Melee DPS, Healers)

AbacusLib

Assist you with faction transfers letting you know which mounts, spells, etc you have and what they will be swapped to.