I went out to look for some today. I live in the Netherlands, and I couldn't find any online either. I visited all three game shops in my city, and none of them had them in stock.
In the first one, they still had two Sanrio-packs for 6,50 euro each so I picked one of those up, but they couldn't find or order any other Amiibo cards at all (any series). The second one didn't have anything either. They didn't have it in stock, nor any of their other locations or in their distribution center.
The third, and last, one I got to had quite a bunch of cards of the 1-4 series, but none of the WA. He checked his system and could find 3 packs of WA cards in
all of Holland. So I reserved those and they're coming my way.
When I asked him if they would get more, he said he had no idea. Distributing these packs had been vague and unclear from the beginning, he said, with Nintendo themselves not knowing when or how many more there would come. Should he get some more, it would just be lucky and I shouldn't expect it. When he ran out of stock of the first four series, it would go the same way as now with the fifth (they wouldn't know what to expect).