I've come across many articles (no. 14 on this, and no. 3 on this, for example) advising the addition of , partnerat the end of a query to return only official videos, i.e., videos from partner channels. However, such a query does not seem to work on YouTube. It just treats partner as a part of the query and returns results according to that. Any workarounds?
Advanced search query to return only official/partner videos on YouTube
youtube