The beauty of Android is the huge ecosystem of awesome open-source apps available for the platform. There is an entire app store called F-Droid that exclusively features free and open-source apps.

Cutie-Pi turns a Pi-hole display into a retro pixel-art dashboard showing real-time stats. Swipeable screens (stats, graphs, clients, system info), 8 themes, optional CRT scanlines, touch/keyboard.

If Windows is your preferred operating system, consider these open-source apps. There are numerous open-source apps available for almost any task. These are all free to install and use on Windows.