WowAce

Alert your friends when you ding, get an achivement, or get phat lewts!

Hides the Order Hall Command Bar

Add TomTom Waypoints for Flight Masters in classic

Adds notes to item tooltips

Filters unimportant Buffs.

ShammySpy

SupplyAndDemand

Surfaces

Status indicator that shows if a unit is hostile (probably mindcontrolled)

Mute error messages of N next spell cast.

tekProber

Helper addon for the Zul'Drak daily "Troll Patrol: The Alchemist's Apprentice"

AvionComicMedia

Tracks spiritual innervation on Garajal

Compact scrolling vendor frame

Whats

Shows a countdown bar for the duration of auras (e.g. HoTs, DoTs)

Opens professions and shows their skill level.

ControlFreak

Baggins_ItemRack