Mac Dock Stacks and Window Previews: Find Files and Windows Fast
Drag any folder into Apple's Dock and it becomes a stack. Control-click it to choose the sort order and whether it opens as a fan, grid or list. Appish reports that hovering an app in Apple's Dock shows only its name, though third-party apps can add previews. In a Moor dock (macOS 26 or later), Downloads shows each file's age, and running apps show live window previews once you turn them on.