WowAce

Hemlock

FuBar_PetFu

Allows customisation of login/logout system messages.

Show coordinates on minimap

KC_Mobility

BiGOpt

Speed plugin for any DataBroker display.

Announces Mage Spells in chat.

Add item levels to Inventorian

Adds a button to your character and inspect window that shows a summary of gear enchants and gems.

T_Tracking

oUF element for highlighting debuffs that are dispellable by the player

Simplifies GDKP bidding processes

Interacts with TinyTip modules, either integrated or standalone, to provide extra centralized functionality. Required for an ...

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

SinkLib

HazLoot

AltClick an item in your bag to add it a mail, auction, or trade frame, and alt-click to buy a stack if reagents.

Quest helping: fetching items to use, that sort of thing.

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