Currently when creating a Query Panel, there doesn't seem to be a way to define what query to search for. As an example, I would like to make a panel that lists Tasks that are "Needs Triage" and add it to my Dashboard, similar to Phabricator's default home page. It looks like there are a few pre-built queries (like Assigned, Authored, etc) which are useful, but my example for a Priority isn't available.
I know you can create Advanced Search Queries in the search screen and save them - even being able to select one of my saved queries from that list would be sufficient for this functionality.