Marlin is described as 'new GTK3-based file manager for Linux, pretty slick and fast.
Unlike most other file managers Marlin has included the so called "Miller columns" view' and is an app in the File Management category. There are more than 50 alternatives to Marlin for a variety of platforms, including Windows, Linux, Android, Android Tablet and Mac. The best alternative is Double Commander, which is both free and Open Source. Other great apps like Marlin are Total Commander (Freemium), XYplorer (Paid), Dolphin File Manager (Free, Open Source) and FreeCommander (Freemium).