WowAce

Mute all sounds except boss emotes and addon sounds

Very very simple tooltip

Manage your AddOns while logged into the game

Out of Mana bar.

Meant To Do That

Simple item compare tooltips

Addon to manage WoW titles.

Adds Outfitter filter to Baggins

PhatLoot

Manasurge

A library to provide unobtrusive notifications.

Displays the internal cooldown of Eclipse as a ClassTimer bar

SpiritedCrane

Save, load key bindings, set autoload for specchange, etc

Auto sizes frame layout depending on group/raid size

LibGUIDRegistry-0.1

Makes out-of-range buttons red. Super efficiently!

Show a bar indicating the unit's Burning Embers count.

RuinBossTactics

Grid status module that shows the remaining value of any effect tracked by AbsorbsMonitor