WowAce

Shows ZoneInfo on the World Map in a perfectly cromulent fashion.

FuBar_HonorFu

SpyGnome

Tracks skill and tradeskill costs and progressions, as well as trainer locations.

Load manager for AddOns

Aura alarm.

ArcHUD2

ItemPriceTooltip

ArenaMaster

Quickly see what counter-combinations your epic followers cover and which ones are likely to get a new combination when rerol...

Some handy events that should exist in the default UI

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

Gives a score for your kit allowing easy comparison with others, also colour codes kit based on appropriateness for your level.

FuBar_PuntFu

InfiniBar-2.0

Arcana-LFG is a broker plugin to show looking for group information, including call to arms

Role playing AddOn that shows extra information about characters as entered by the player.

FuBar_AmmoFu

Manages social information with a focus on main-alt associations.

Keeps track of current money and all your characters on one realm.