What Are Those Little Plastic Nintendo Figures Called? amiibo

They're called amiibo (pronounced "ah-mee-bo").

amiibo are NFC-enabled figurines that interact with Nintendo Switch, Wii U, and 3DS systems. Tapping an amiibo to the NFC reader (right Joy-Con stick on Switch, GamePad on Wii U) unlocks in-game content: costumes, weapons, characters, save data, or AI partners—depending on the game.

Popular lines include Super Smash Bros., The Legend of Zelda, Mario, Animal Crossing, and Splatoon. Some games also support amiibo cards as a lower-cost alternative.