Itch.io has a press section. (Find it under your profile.) I believe it was deactivated for a while due to abuse, but it seems to be active again. If you opt in, people can download your games without paying in order to review them. (But there's no proof that the people are actually going to review them. )
As far as I know, that's the only system that lets someone download your game without paying for it.
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