macOS High Sierra 10.13.5 supports the following Macs:

As the engineers worked their magic, a peculiar thing happened. One of the team members, a quirky and lovable developer named Alex, stumbled upon an unusual idea. What if, he thought, they could create a digital artifact that would allow users to experience the thrill of installing and running macOS High Sierra 10.13.5 on their own machines?

(Note: that command creates a bootable USB, not an ISO. Convert to ISO only if you need it for virtualization.)