WowAce

Library handling communcation for Magic* addons

Adds unreal tournament style sounds to PvP encounters.

Mutes various chat related annoyances while in capital cities and instances.

Open all your mail

Manufac

Litmus

In-game EPGP guild helper, supports standby, main/alt shared pools, minEP, offpecGP. Fixed price list with progress multiplier.

Track all threat redirection ability transfers and cooldowns (Misdirection and Tricks of the Trade).

Mutt (Macro Update Target Tool) provides slash-commands that can patch the predefined targets in your macros.

Add item levels to Inventorian

KillingSpree

Show what quests have changed

Gathers statistics on certain chance-on-use spells, also known as procs.

Adds your name to chat messages

PT3Browser

Priority 3 loot announce addon

MorgDKP

manipulate the minimap in numerous ways; move, scale, skin.

Shows simple Buttons for your Cooldowns :)

Simple right click casting.