WowAce

Arena unit frames

Replacement for the default UI's StaticPopup dialogs.

A library allowing for easy creation of graphs

Simple AceGUI3 dropdown item classes for font/statusbar/sound/etc.

Parses ToC and adds About panel to Interface options

The original source for where things are in Pandaria

Tracks Raid/Instance/World Boss lockouts for all your characters, daily/weekly quests, currencies, trade cooldowns, and more!

Keeps track of group members and keeps an up-to-date cache of their specialization and talents.

Another HUD addon

Estimated range display. Type /rangedisplay for config

Database of item upgrade IDs

Adds a Button to the Worldmap which toggle Handynotes

Ackis Recipe List is an addon which will scan your trade skills and provide information on how to obtain recipes. It works fo...

Officially the original source of knowledge of where things are in Draenor during Warlords, in HandyNotes

Simple Map Mod

Shows the possible loot from the bosses

Modular damage meter.

The original HandyNotes source for where things are in Battle for Azeroth

In-game theorycraft. Calculates actual damage/healing based on gear, talents and buffs.

A friendly companion that remembers the chat.