When I got my Welcome Amiibo cards I bought 5 packs and didn't get a single double so I got most of the ones I wanted (except for Ketchup!!), from regular packs the only "good" one I got was Deirdre but I lost that card anyway haha
In my very first pack I got Goldie! I was super happy when I got her since she's one of my dream villagers!
I also got Robin in a pack a few days ago, she was accompanied with Jacques and Brewster which I thought was pretty cool. (All birdies)!
If we're talking about good deals on individual amiibo cards, I'd say my best finds were Marshal, Ankha, and Merengue for $2 each on eBay before the update. Random pack-wise, my best finds were Julian and Lucky. I was so happy to get them when I opened up the packs they were in.