You might call them “unpledged delegates” or “superdelegates,” or perhaps you prefer “automatic delegates” or “democracy spoilers.”
At any rate, if you’re interested in lobbying the 800 or so people poised to determine the Democratic nominee for president, this map based on the superdelegates.org wiki can help you find them.
(Thanks, Marc Ambinder.)
Image by Lokal_Profil,licensed under Creative Commons.