By default, Google’s Product Listing Ads have 10 or less products in their mobile carousels.  While we have seen them play with having two carousels, one on top of the other, most product carousels are still fairly limited in the number of products.

Google is testing a new version of their Product Listing Ads Carousel with 30 products instead of the usual 10 or less.

It looks like a standard carousel, but in addition to the 30 products, it also included the keywords carousel to narrow it down more:

When you scroll all the way to the end, it also just looks like a standard PLA carousel:

This seems to be a test they are running with specific products that have a higher number of potential product matches, as I was getting the 30 product carousel pretty consistently for this query over a few weeks across browsers, but not for other product queries.  So there could be other queries with high product volume that also trigger these super sized PLAs with 30 products.