WowAce

Minimap addon of awesomeness. *chewing sound*. It'll nibble your hay pellets.

CT_RaidAssist style raid frames

Antagonist

Unit Frames of awesomeness. Woof. It'll bite your face off.

AddOn development framework

Tracks herbs/ore/items that can be broken into component pieces

Show the transmog appearance of an item when you mouse over it, and shows collection-status in bags, shops, and elsewhere. Works on transmog, mounts, pets, and decor.

Set and manage character notes that are displayed in unit tooltips and /who results.

XP bar using Ace3.

StatLogicLib

EBB adds groups of bars to your screen showing you which (de)buffs currently affect your toon or some other units.

Shaman totem bar

Reports on a configurable dashboard or to group chat on consumables, buffs, AFK, mana and many many others but in an intellig...

Numerical and graphical display of Combo Points and similar buffs/debuffs. Also tracks Holy Power and Soul Shards.

Displays the locations of Lunar Festival elders.

Complete tradeskill information.

Timers for Buffs, DOTs, CC effects, etc..

Lightweight but powerful auction house interface

The Talent Template Editor

Remember locations that city guards direct you to for HandyNotes