My trial period on extFS for Mac by Paragon Software (11.1.657) has expired, and I don't intend to renew the licences, but I cannot figure out how to uninstall it.
I came here looking for this answer and was a bit surprised that no one had answered it. I'm even more surprised now that I know how easy it is.
For those that arrive here in the future, all you need is the extFS .dmg that you downloaded to install extFS. If you already trashed it, just download another copy. Once you have that, open the .dmg file and you'll find two items: an installer, and an uninstaller. You'll be prompted to restart after you uninstall.