Vaguely fun thing I discovered -
https://www.youtube.com/results?search_query=Podnews&sp=EgIIBxgA
This search query to YouTube is a scoped search to *just* search for podcasts. The "sp=EgIIBxgA" bit is the filter you want. If a creator hasn't marked their content as a podcast, it won't appear in this search.
I've, boringly, sent a feature request for that filter to be surfaced somewhere in the YouTube interface. Because that would be nice, wouldn't it?