I guess these are google Featured ads, its a new feature, soon will be implemented with all the adsense publishers, but for now, i think they are testing it with few publishers only. More info can be found here.
They are another way of advertising featured ads! Google are currently running a test in which a small number of users are seeing these ads that are marked based on signals related to quality and relevance. This is all part of Googles methods in trying to bring people what they are looking for better. So its just like an updated version of featured ads.