You're probably talking about what we like to call "Nordgens". These mystical creatures appear daily on the Auction market with randomly generated team names like "AC Funny", and are often some of the best-valued players on the market. However, they only appear at certain times; I get them most often at around 4:00 AM GMT. Also, some days they're all high-level 5* players, and other days they're all terrible 3* players, so you sometimes have to check multiple days in a row. They're a little bit finicky, but if you can get your hands on some, they're definitely worth it.