Omen3
A lightweight, flexible, multi-target threat meter.
Cataclysm 
The Burning Crusade 
Wrath of the Lich King Addon Details
Expansion
Categories
Developers
Having issues?
Basically, enemies in WoW decide who to attack by deciding who is the most threatening based on the abilities you use. What Omen does is provide accurate values of your group’s relative threat level on individual enemies, so that you can see when you’re in danger of pulling aggro
Download Omen3
Mists of Pandaria
5.4.8More addons for Mists of Pandaria
Discover other addons that might interest you
GinkoText
Changes your in-game floating combat text in to a calligraphy stylized font.
KuiNameplates
Prettier nameplates.
hcGossipBot
Automated interaction with questgivers and other NPC's.
Healers Have To Die
A simple Add-on that rings when you hover or target an enemy healer.
DebuffFilter
Filter out specific debuffs and buffs into separate frames.
SanityCheck
This won't teach you to play better; but it will make sure to remind you…
Achievements Reminder
Informs about achievements when you enter the instance or target the boss.
EasyLoot
An automatic loot filter.