Here's the situation, the first two entries to be exact (second one brushed):
This does not seem to be related to autofill suggestions in the search bar, which are set to be off in my case - these keep popping up. I can't remove them via delete/shift delete, as suggested in another topic.
That's not a problem, since I can click dismiss, but I'd rather disable their appearance once and for all; it seems like Chrome saves some of my YouTube (and potentially other website) searches and then suggests them to me. Saved forms are off to me as well, emails/passwords etc. don't get saved.