WowAce

Provides the ability to suppress specific spellcasts like "Deaden" from your casting bars.

Doodle

Restores channels and channel-window associations after disconnects remove them.

Make it easy to explain bosses in Raids.

Bars showing amount of buffstacks

SpyGnome

GemCensus inspects people and records which gems they have socketed. Then displays which gems are the most popular.

DogChow

Adds cooldown timers to your trinket procs

PriceTag

Allows you to prevent addons from sending and receiving messages.

Artifact power bar support for oUF layouts

Don't underestimate your little critters!

Displays an alert whenever you loot an item for the first time.

A Data Broker display for combat statistics.

Displays a variety of useful stats for tanking

ArenaMaster

Lets you drag UI frames around

Warnings about tanking specific abilities

tekSupport