nanDECK is described as 'software for Windows (any version) written as an aid for game inventors, with the aim of speeding up the process of designing and printing deck of cards (useful during prototyping and playtesting)'. There are four alternatives to nanDECK for Online / Web-based, Windows and Steam. The best alternative is Anime Yu-Gi-Oh! Card Maker. It's not free, so if you're looking for a free alternative, you could try ADL Interactive. Other great apps like nanDECK are Card Creator (Paid) and MakePlayingCards (Paid).
Card Creator is a Windows desktop tool for creating card designs for card, tabletop and other types gaming. Create any kind of cards without coding or drawing, using any card formats you can imagine using the Card Blueprint tools.