WowAce

Records mail when visiting the mailbox to make keeping track of mail and expiration dates easy.

Allows you to create icons, which can be customized greatly by user's input. CiR is more than just the usual cooldown tracker.

Avion

Displays info about who rolled Need/Greed/Pass on items that are currently rolled for

Shows optimal target to use various area healing spells

A death track window for Recount

FelwoodFarmer

wRlog

CraftList

FuBar_ChatAlertsFu

Color manipulation library.

Displays an animated bar with next enemy swings

What actual item level is an item? Yes, it's horrible we need a library for this.

TouristLib

Shows current/dot cast haste values

AddOn to Manage Roster and DKP for the guild

SkadaScroll is a plug-in for Skada Damage Meter that provides additional options for scrolling the bar displays. It requires ...

A simple range indicator for optimizing Halo damage.

A Data Broker plugin to show AddOn memory usage.

Warnings about tanking specific abilities