Do you have an old PC lying around gathering dust? How about a small-capacity USB flash drive sitting, unloved in a drawer? You can reuse your old computer and a USB flash drive by installing a tiny Linux distribution.
Mini Linux distros are great as they require fewer system resources than other options yet still deliver a whole operating system experience, and we have nine of the smallest Linux distros for you to choose from.
This article is pretty old and some of the distros suggested are no longer effectively maintained.