In this section I am gonna post useful addons that will help you increase your dps and only this kind of addons. Don't expect me to post any kind of decorative or quest helping addons etc etc.
Omen is a threat meter.
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 (or, if you're next on the snack list if your tank bites it). This info is usually only critical in raids, where only tanks can survive aggro, but it's useful for any multi-player situation.
This addon warns you when you are running out of mana so you can change to Viper or when you are almost full and still have viper on it warns you again to change aspect. The threshold is customizable to whatever number in % you want. ie you can set it to warn you to change to viper at 10% or 5% or even 60%. It warns you with a sound and a screen message so it's not easy to forget to change.
Notification message can be displayed through floating combat text or raid warning. Supports Blizzard's Combat Text, SCT, and MSBT.
OmniCC is an addon that adds text to items/spells/abilities that are on cooldown to indicate when they'll be ready for use. OmniCC should be compatible with any addon that uses a cooldown model.
A configuration interface is included, and can be shown via /omnicc or /occ
NeedToKnow lets you monitor specific buffs, debuffs, and totems as timer bars that always appear in a consistent place on your screen.
NeedToKnow is especially useful for monitoring frequently used short-duration buffs and debuffs. For example, a rogue could configure NeedToKnow to show timer bars for Slice and Dice, Rupture, and their own stack of Deadly Poison VII. A death knight could use it to track their own diseases on a mob.
Simple addon, all this does is speeds up triggering actions by making them happen when you press a key or press your mouse rather than releasing them. It's setup to work with all of the default Blizzard action bars as well as totem summoning and recalling. It will automatically work with any addon that uses the default Blizzard system for key bindings (Game Menu -> Key Bindings). Even if an addon doesn't work with Speedy Actions I can add a module to make it work, just see below.
There is no real performance cost from using this addon either, the work it does is out of combat and while in combat the only "cost" is that of executing a key binding.
