Using acoustic fingerprinting, the AcoustID database, Yate's best release matching and MusicBrainz, unattended metadata lookups on tracks with little or no metadata is possible.
There is a fully documented preloaded action called Unattended Metadata Lookups. The action is designed to be run in the Batch Processor Wizard.
As the action was only preloaded starting in v3.7 you will not have it preloaded if you initially installed Yate prior to v3.7. You can import the set of updated preloaded actions by holding down the Alt (Option) key and selecting the Yate>Reset Built In Items>Import Actions menu item. Note: make sure that you hold down the Alt (Option) key, otherwise you will overwrite your existing actions. After the import the action manager will have a Preloaded Actions folder. The action is also available for download on the Resources web page available from the Help menu.