WowAce

Should I send that recipe to my alt?

Open those clams (and other containers)

Library for tracking cooldowns of other players

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

wRlog

Cartographer_NoteTarget

Prompts for canceling of pet battles if no rare pet is found in the opposing team.

kgPanelsConfig

Percent

Announces ooze kill instructions during the Yor'sajh encounter in Dragon Soul. Highly customizable with numerous helpful feat...

BagSync

Voyeur

Database of Mailbox locations for HandyNotes

A fully featured library tracking all ongoing absorb effects

What did you just loot?

Splut

Cartographer_Mailboxes

Keeps track of healing spells cast by everyone in a group.

GratuityLib

Draws some lovely 3D portraits in the standard Blizzard artwork.