Fort Firewall

Fort Firewall is a open-source firewall for the Windows platform.

https://github.com/tnodir/fort

https://www.howtogeek.com/these-open-source-firewalls-do-what-windows-defender-cant-and-theyre-free/

Nova Media Player

NOVA is an open source video player for Android.  It can be used on Android TV as well.

https://github.com/nova-video-player/aos-AVP

https://www.howtogeek.com/my-favorite-fire-tv-app-has-nothing-to-do-with-streaming/

Sefirah

Sefirah is a free utility to allow clipboard and notification sharing between a Windows PC and Android device.

https://github.com/shrimqy/Sefirah

https://www.androidpolice.com/forget-phone-link-this-ad-free-open-source-app-beats-it-in-every-category/

Multipass

Multipass is a free application from Canonical.  It’s basically a lightweight virtual machine manager: it downloads an official Ubuntu image, spins up a VM using your computer's built-in virtualization technology, and drops you into a working Linux environment with a single command.

https://canonical.com/multipass

https://www.howtogeek.com/the-company-behind-ubuntu-also-builds-these-surprisingly-useful-developer-tools/

WUView

Windows Update Viewer (WUView) is an application that displays Windows Update history. It is meant to be a lightweight application that is easy to use.

https://github.com/Timthreetwelve/WUView