WowAce

Shows where the equipment of inspected users or yourself is from.

Automatic ammo reloading and selection, with warnings.

Adds Buff/Debuff icons to the grid frame.

BigTrouble

Enables you to see Chinese, Japanese and other languages in game

FuBar_ShardCountFu

GridLayoutPlus

Parkour puzzles throughout the world.

Data broker for keeping track of your Ankh cooldown.

EquivalencePoints

Used to visualize and change values of variables/variable-trees in game

Warnings about tanking specific abilities

BigWigs_HealbotAssist

A 'channeling spell'-tracking addon for Affliction Warlocks. Drain Soul, Drain Life/Harvest Life and Malefic Grasp.

NextStep

Information display for Hunters.

AltClick an item in your bag to add it a mail, auction, or trade frame, and alt-click to buy a stack if reagents.

Checklist and notes addon.

Assistance to the dance during Dread Spray

Bidder for DKP points. Usable as standalone bidder, or with DKP - Manager to manage points.