There are many open-source software options available for Windows, and the best ones will depend on your specific needs and preferences. Some popular open-source software options for Windows include:
LibreOffice: A productivity suite that includes word processing, spreadsheet, presentation, and other tools, and is compatible with Microsoft Office file formats.
GIMP: An image editing and manipulation program that is similar to Adobe Photoshop.
Audacity: An audio editing and recording program that is widely used for podcasting and music production.
VLC Media Player: A media player that can play a wide range of audio and video formats, including DVDs, CDs, and network streams.
Mozilla Firefox: A web browser that is known for its privacy features and support for open web standards.
7-Zip: A file archiver and compressor that supports a wide range of formats, including .zip, .rar, and .7z.
KeePass: A password manager that allows you to store and manage your passwords in a secure way.
OpenVPN: A virtual private network (VPN) client that allows you to securely connect to a VPN server.
These are just a few examples of open-source software options for Windows, and there are many others to choose from. You can find more options by searching online or by using an app store that focuses on open-source software, such as the Open Source Software Directory.