I listen to a lot of old music... like 1920's - 1940's old. So it's usually a surprise when my Spotify suggestions aren't filled with singers such as Doris Day, Dean Martin or The Andrew Sisters. It's probably because of The Andrew Sisters that I was recommended The Puppini Sisters.
Even when I get newer singers they're rarely ever that contemporary. I was instantly hooked when I first hear them. Especially when I heard their covers of contemporary songs with a 1940's twist.