WowAce

Aspect checker addon for Hunters.

Auto sizes frame layout depending on group/raid size or predefined zone data

LDB Broker launcher for HealBot

This is an add-on to block incoming guild/party/duel requests (except for friends/party/guild) (previously ASSBlock)

Crowd-control monitor

Keeps an eye on someone's distance from you, and alerts you if they get too far.

A menu with useful searches for Inventorian

Allows you to prevent addons from sending and receiving messages.

MiniChat

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

Gives a Smoother Quest Experience

Swiss Army knife for instances, including player tracking, ignore buttons, loot tracking, notes, and more.

SwapMagic

SmartQueue

FuBar_ButtonSmashFu

Makes tracking reputation much simpler. By InSo(v)nIaX

Allows customisation of login/logout system messages.

Saves contents of your guild bank and sends/receives updates over the addon channel

GetInLine

Does a /who search of multiple dungeons.