Based on talent, Ivan Cavaleiro is up there with the very best on this list. He's incredibly talented for a 21-year-old and could easily develop into the world's finest, but taking him out of Monaco will be a mighty challenge. If you scout for his talents, your scout will return with double figures in the 'pros' list, with the only 'cons' being that he is not interest in leaving permanently or on loan. He comes with a £21.5m release clause and low wages mean that the second he agrees to even discuss a move away from Monaco, you have a chance.