Like most Nintendo Switch games, Fire Emblem: Three Houses offers a little bit of amiibo support functionality. This is done in game at a place in the monastery called the "amiibo Gazebo", which is found in the field above the dining hall.
Using amiibo ultimately does two things. Firstly, each Fire Emblem series amiibo will unlock a different music track for use in auxiliary and quest battles, which can be set in the game's menu.
Secondly, using an amiibo at the amiibo Gazebo will cause it to start dropping green pick-up items every time you explore. As long as you use at least one amiibo, it seems you can find new drops in the area around the Gazebo every week. These drops often include bait, fish, tea, and basic consumables. However, you rarely might be able to get stat up items from this too.
So, if you have at least one Fire Emblem series amiibo, you might as well use it at the Gazebo as soon as you can in order to get some items.
Want more Fire Emblem: Three Houses help? Check out our full Fire Emblem: Three Houses guide and walkthrough, which ranges from beginners tips to advanced strategy.
Fire Emblem: Three Houses - amiibo Music Unlocks
By scanning the following amiibo at the amiibo Gazebo in the monastery, you can unlock the following map songs for auxiliary and quest battles.
Alm amiibo - March to Deliverance
Celica amiibo - With Mila's Divine Protection
Chrom amiibo - Destiny (Ablaze)
Lucina amiibo - Conquest (Ablaze)
Female Corrin amiibo - A Dark Fall (Fire)
Male Corrin amiibo - Alight (Storm)
Ike amiibo - Eternal Bond
Marth amiibo - The Time to Act
Robin amiibo - Id (Purpose)
Roy amiibo - Beneath a New Light (Roy’s Courage)
Tiki amiibo - The World Tree