Google seems to be rolling out a new carousel feature set for shopping ads. This was covered by Ginny Marvin back 3 weeks ago, but now it seems more and more people are seeing it.
When you search for specific retail or shopping queries, Google may show you a carousel that lets you refine and filter your search results. The categories let you 'refine by style' and other options.
Here is a screen shot from Glenn Gabe on Twitter:
I am personally able to replicate this, so it seems to be live for many.
Forum discussion at Twitter.
Update: This is supposedly an organic feature not ad feature:
@rustybrick BTW, this is not a shopping carousel, it is an organic search feature. Just some happen to show PLAs.
— Jennifer Slegg (@jenstar) December 9, 2016