A new Half-Blood Prince TV advert was recently aired, showing new scenes with Harry, Ron and Hermione in the Gryffindor Common Room; Slughorn’s Potions class; Harry, Hagrid and Slughorn in Hagrid’s hut, and more. I will update this post when there is a clearer version online. We see Neville in a few parts, around 10 seconds and 26 seconds.
Thanks SS!