WowAce

Keeps track of performance of memory, latency, and framerate.

Cartographer_Herbalism

Shows mana usage as a percentage in a spells tooltip.

eeShards

YssGuildShop

Creates virtual cyphered chat channels over guild addon communication channel.

SacredBuff

Broken in Midnight. I recommend MidnightFocusInterrupt instead.

OneBank3 will combine all the bank bags into one frame.

ItemPriceTooltip

Switch macro depending on zones or BigWigs boss modules.

Find five Ephemeral Crystals, get a pink hippogryph

Provide plenty of links

Keeps track of durability and pops up a dialog to repair when you go to a vendor who can.

A Collection of Automations and Interface Tweaks.

Kiwi Plates

Database of item upgrade IDs

Provides quick access to information on your group and their equipment, enchant and gem choices.

Shows where the equipment of inspected users or yourself is from.

Keeps track of space left in your bags.