WowAce

Calculates incoming damage avoidance and mitigation

Provides buttons and keybinds for raid flare world markers that never stop working mid-session

Debuff Monitor: A Powerful & Configurable Raiding Tool

WhiteboardNG

Angry Boss Reminders helps raiders switch to the proper talents, glyphs, and gear for each boss during a raid.

FuBar_RLAssistFu

Puts a timer in /yell when you get Unbound Plague during the Heroic Professor Putricide encounter

NielasAran

A boss encounter engine used by other add-ons

Shows a window displaying any raid member below 10,000 health during the Chimaeron encounter.

Tells you which blob to kill at the Yor'sahj encounter in Dragon Soul.

MoBuffs

AutoAcceptInvite

A loot distribution addon meant to improve master looting during raids.

Handles the assignment, coordination, and announcement of many parts of the Lich King encounter in Icecrown Citadel.

Helps you see the Halion's Corporeality during phase 3

nRaidTracker

Lists and/or reminds people missing flasks or food buffs at every ready check.

Shows the minimum durability of equipped items on the stats frame.

Displays both Kalecgos and Sathrovarr the Corruptor hit points during the encounter.