WowAce

Sets you to DND when you fight a boss, and some other crap.

Allows custom-triggered boss mod timers to be created

Resizes Blizzard raid frames, and adds additional options.

Provides data about all artifacts in the player's possession.

ezIcons

Notifies you of new calendar event invites and reminds of upcoming events on all characters and realms

Adds support for LibFilter to Baggins

Merchant, gossip and taxi tweaking module for TweakHub.

Gnomish math at its best!

Shows all the targets in the raid

Light-weight enhanced casting bars

Adds achievement reminders to BigWigs

Simple search inspired by vBagnon

BangItHarder

FuBar_FromAViewToAKillFu

A Fail main view module for Recount

TickTo

Keeps track of important de-/buffs in a splash screen

A simple addon that warns you if your pet isn't attacking while you're in combat.

Shows loot information in item tooltips