WowAce

Drop the cheapest thing you're carrying

Entertaining kill-shot notification.

Provides a quick display for the LFG Call to Arms

Adds spec switching support to individual AceDB-3.0 databases.

Toss those bugs inna sack.

Core module for Loot and Looting-related UI improvements

Reno is a slash-command that can patch predefined options in a macro to change which actions will be chosen.

Mutt (Macro Update Target Tool) provides slash-commands that can patch the predefined targets in your macros.

Another HUD addon

Grabs bugs for the bug sack.

Mutes various chat related annoyances while in capital cities and instances.

Adds a Button to the Worldmap which toggle Handynotes

Changes the look of the default UI

Displays information about the current zone on the World Map for WoW Classic Era

Good old LibTourist-3.0 for WoW Classic Era

Library of compressed itemid sets.

A friendly companion that remembers the chat.

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!

Officially the original source for where things are in the Broken Isles, in HandyNotes