WowAce

Simple display and management of Away / AFK / Busy / DND status via broker or minimap

Library handling communcation for Magic* addons

Niagara

mHud

Displays online guild mates.

Manages tracking of raid attendance, loot, and more.

A small checklist for raid (de)buffs and who brings what.

Tells you if you're buffed

Tracks profession specific cooldowns and items across all your characters

Display bag usage on each of your bag slots.

Bind spells, items, and macros to keys, without using action buttons

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

Displays friend notes in unit tooltips, at logon, and in /who results.

GDKP gold run ledger

Auto roll greed, need, pass or manually roll on items.

CCBreaker

FuBar_MicroMenuFu

Enhancer

Rep2 displays a message, which shows how much reputation you gained, and how much is needed until the next standing.

Loudmouth