In short, CT_RaidAssist reports hp, mana, buffs, and debuffs of anyone or everyone in your raid. You can set it to notify when someone is debuffed with specified types as well as notify when buffs you can recast fade.
SW Stats (named after our guild Shadow Warrior) is a damage/heal (and more) meter addon designed to be very customizable in what you want to see with a built-in Sync channel that is running in the background.
KLHThreatMeter is like a damage meter, except it records your threat. By monitoring all the abilities you use and checking your talents, armour set bonuses and buffs, the addon can recreate the threat list of a mob. This makes tank transitions simple