Figma Mirror is described as 'allows you to view your designs from the Figma desktop app live across all of your mobile devices'. There are five alternatives to Figma Mirror for a variety of platforms, including iPad, iPhone, Android Tablet, Android and Windows. The best alternative is Lunacy, which is free. Other great apps like Figma Mirror are Adobe XD Mirror (Free Personal), Design Mirror (Paid), Sketch Mirror (Free) and Framer Preview (Free).
Lunacy is a native Windows app that opens, edits, and stores .sketch files. In short, it’s long-awaited Sketch for Windows. It solves the big pain of design teams working on different operating systems and improves the process of transition from design to development.