You may know of the gPodder.org site, which among other things, has a web-based endpoint that returns OPML for searches and its own top list of feeds.  To do more with it, you must create an account.  With an account, you can manage a centralized feed list and sync it amongst your desktop and multiple other devices.

This is the main motivation for adding OPML support to Synder, so we can provide you with access to a great source of feed discovery!  We have gone so far as to pre-load those URLs into the Feed Farmer startup lists.

This is also the motivation for providing generated “Add Feed” and “Preview Feed” links into the content for OPML results.

The only downside so far is availability.  The search endpoint has been “down for maintenance” for several days.  Hopefully that doesn’t last too long.