I highly recommend purchasing cards from here. They work perfectly. As long as you don't care that it's not an actual amiibo card then I suggest buying these. We don't care what the cards look like we just care about the villagers. The cards are slightly bigger and have a printed sticker a fixed to them so it looks like the real amiibo cards. But don't get me wrong this is a real amiibo card because it brought the villagers to my island.

worked fine

Low resolution images and sloppy sticker, but they work and I love my new villagers! <3

Eugene - Villager NFC Card for Animal Crossing New Horizons Amiibo

Card was in excellent condition and order was shipped fast.