Although the rise of interest in the properties of graphene over the past decade has been remarkable, it also underlines a long-standing fascination that materials scientists and condensed-matter physicists have with 2D and layered crystals more generally. The latest systems to have gained widespread attention are the transition metal dichalcogenides such as MoS2, which combine many of the appealing structural and electronic characteristics of graphene with semiconducting behaviour, a desired property for many technological applications. Doubtless there will be many more such 2D systems to come. Predicting quite how many and, more importantly, which materials are the most promising for experimental investigation, is the object of the latest study by Sébastien Lebègue and colleagues. By filtering structural data contained in the International Crystallographic Structural Database and combining this with first-principles numerical simulations to predict their electronic and magnetic properties, the researchers provide a glimpse to a far larger landscape of 2D crystals than previously imagined.