WowAce

A boss encounter engine used by other add-ons

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

Test whether the player can really dispell a buff or debuff, given its talents.

Target assistance by automatic rewriting of macros

LFD status via a DataBroker display rather than the minimap.

Show a rough range indicator

Puts a timer in /yell when you get Unbound Plague during the Heroic Professor Putricide encounter

TalentWhisper

FuBar_TinyTipFu

FuBar_combatTextFu

A simple data broker display for current Artifact Power

Shows who controls Wintergrasp and the time until the next battle.

Enable/Disable addons for your character in game

Database of Mailbox locations for HandyNotes

PVPtimer

Embeddable library to track raid/party roster

Advanced Chat Filtering and Spam Blocking Addon

Raid target control and instance shortcuts for Broker

Quest information

"Shows Call To Arms status in an LDB data provider."