PMVHaven Instant Downloader от Taqy

Works without an account on PMVHaven.

This extension adds an instant download button that when clicked will instantly download the video of the current page with the video title as the filename.

It also adds a button to open up video links in a new tab.

There's an option to add the creator into the filename, either before or after the title. And also the ability to download videos with the default filename given by the server.