WowAce

Scan for rare mobs so you can find them and their loot

Show the appearance of an item when you mouse over it

Show item levels in the character frame

Point to quest POIs on your minimap

Drop the cheapest thing you're carrying

Library of data about what items tier tokens can be turned in for

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

Show what quests have changed

Show a texture on demand

Library to check whether an item is equipable / appropriate for a given class

The original source for where things are in Pandaria

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

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

Remember locations that city guards direct you to for HandyNotes

Add item levels to Inventorian

Open all your mail

Should I send that recipe to my alt?

Speed plugin for any DataBroker display.

Show all the orbs for triggering Kosumoth

Show where the chests are for Withered Army Training