All official WPFTS Add-ons are free and only work with the Official WPFTS plugin version.
Did you not find an addon for your plugin or theme? Write to us. We will develop an addon or patch for your case.
WPFTS Add-on for WP-Filebase Pro
Makes WP-Filebase Pro files indexable and searchable by their content
WPFTS Add-on for WP Download Manager
Makes WP Download Manager files indexable and searchable by their content