https://www.xnview.com

• jpeg-xl 0.1 support was added in Version 0.97.0 (Tracker)
• jpeg-xl 0.3 support was added in Version 0.98.2 (Tracker)
• Changelog

https://imageglass.org/
https://github.com/d2phap/ImageGlass

• jpeg-xl support was added Jan 9 2021 (Tracker)
• jpeg-xl support is broken currently, because of a bug in ImageMagick version 7.0.11-3 and below
  (now fixed in ImageMagick 7.0.11-4 / Magick.Native.2021.3.21.236 / Magick.NET 7.23.3.0)

https://imagemagick.org

• jpeg-xl support was added in Version 7.0.10-54
• Changelog

https://squoosh.app/

• Github

Shows thumbnails in Windows Explorer for jpeg-xl files using WIC (Windows Imaging Component)

• https://github.com/mirillis/jpegxl-wic

A JPEG XL (*.jxl) thumbnail handler for Windows File Explorer

• https://github.com/saschanaz/jxl-winthumb

Lightweight Encoder GUI for multiple encoders including jpeg-xl
https://github.com/Alkl58/MegaPixel-Qt

Lightweight Encoder GUI for multiple encoders including jpeg-xl
https://github.com/Alkl58/MegaPixel