Amethyst vs PDF Expert

Amethyst is a free, open-source tiling window manager for macOS inspired by xmonad. It automatically arranges application windows into non-overlapping layouts using keyboard shortcuts, without requiring System Integrity Protection to be disabled. Amethyst supports multiple layout algorithms including tall, wide, fullscreen, and column layouts.

PDF Expert is PDF editor for Apple devices with annotation, editing, and form filling capabilities.. It is available under a paid model. This tool falls under the productivity category.