First, context matters. Visual Studio is a large, complex suite of development tools produced by Microsoft. Official downloads are distributed through Microsoft channels: the Visual Studio website, MSDN/subscriptions (now Microsoft Learn for some resources), and the Visual Studio ISO download pages. These official sources provide the correct, up-to-date installers along with checksums, licensing information, and support. By contrast, an "index of" page typically points to publicly web-indexed directories where files are stored without much oversight. While such listings can host legitimate content, they also draw people seeking shortcuts: archived ISOs that are no longer offered, copies shared without license, or repackaged files.
Since there is no "index" for direct ISO downloads, you can generate the installation files locally using the and command-line arguments. index of visual studio 2019 iso
For enterprises with Volume Licensing agreements, the VLSC provides official ISO images with VL-specific keys. This is the gold standard for legitimate offline deployment. First, context matters