WowAce

Provides one or many informational windows with optional interactive widgets.

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

Tracks rare drops, including companions and mounts

Remember where rares were

Uses various methods to scan your surroundings for rare or specified NPCs.

Where are the hidden treasures in Battle for Azeroth? Show in HandyNotes

Where are the hidden treasures in Legion?

Displays the locations of Summer Festival bonfires.

Where the Lost and Found objects are

Where the Treasure Hunter objects are in Draenor

Adds mob patrol paths to your map.

Achievements

Teleporters in Suramar? Sure, why not?

Displays the locations of the chests for the Treasure, Treasure Everywhere achievement

Where the lore is at

Show all the leyline taps in Suramar

Displays the locations of Hallow's End candy buckets.

Displays the locations of Lunar Festival elders.

Show where the chests are for Withered Army Training

Books in Azsuna? Sure, why not?