WowAce

Allows you to preview weapon glow in Dressing Room.

Keeps track of HoTs, DoTs, Buffs and Cooldowns. With audio and text alerts to refresh them.

Quest History tracker and shows lists of quests in each category

A jukebox for playing wow embedded music.

A library to provide a clean dropdown menu interface.

Checks your gear before bosses and yells at you if you're an idiot

Depot

LDB display of currencies, gold totals and session / daily / weekly statistics for all characters on a server.

FuBar_TrainerFu

Point to quest POIs on your minimap

You've got mail!

Food/water macro generator

Reports in raid chat whenever a raid member "fails." /EnsidiaFails to configure.

TuiRaidTracker

Deathknight Rune Display

A Collection of Automations and Interface Tweaks.

Searches bags/banks of all your characters/guilds.

SacredBuff

Keeps track of current money and all your characters on one realm.

Display bag usage on each of your bag slots.