Animal Crossing: New Horizons
API for critters, fossils, art, music, furniture and villagers
Nintendo Amiibo Information.
AmiiboAPI is a free Games & Comics API that requires no API key, is served over HTTPS and supports CORS, so it can be called from the browser.
AmiiboAPI The Amiibo RESTful API
Details from amiiboapi.com.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
API for critters, fossils, art, music, furniture and villagers
Free Minecraft data: mobs, biomes, items, enchantments, structures, commands, versions, achievements, trades
Diablo III, Hearthstone, StarCraft II and World of Warcraft game data APIs
The AmiiboAPI is provided by AmiiboAPI (amiiboapi.com). AmiiboAPI The Amiibo RESTful API
Yes. The AmiiboAPI is listed in the Games & Comics category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The AmiiboAPI requires no authentication, so you can start making requests without signing up.
Yes. The AmiiboAPI supports CORS, so front-end JavaScript can call it directly.
Yes. The AmiiboAPI is served over HTTPS, so it's safe to use in production.