A trustworthy upload will include:
Archive.org (The Internet Archive) has become the go-to repository for "abandonware" and custom Windows ISOs. Because the site is a non-profit library, it hosts various community-made versions of Windows 8.1 Lite. Popular Versions to Look For Windows 8.1 Lite Archive.org
If you search for "Windows 8.1 Lite" on Archive.org, you will be flooded with results. Here are the three most reputable (based on download count and comments) as of 2025. A trustworthy upload will include: Archive