Google has updated its documentation to provide guidance on implementing structured data markup for large category lists for Structured Data Carousels, such as paginated content or infinite scroll, to enable carousel rich results in search.

Google's new carousel rich result, currently in beta, allows users to scroll horizontally to view more entities from a given site. Each tile in the carousel can display information such as price, rating, and images from your site. Here are all the guidelines:

Guidelines for Carousel Rich Results

To be eligible for carousel rich results, follow these guidelines:

• Search Essentials and General Structured Data Guidelines: Ensure compliance with these foundational guidelines.
• Generic Types and Recommended Properties: Generic types are allowed, but to use recommended properties, you must use the respective types (e.g., amenityFeature requires the LodgingBusiness type).
• Additional Fields: Extra fields can be used but may not appear in the rich result.
• Summary and Detail Pages: Your site must have a summary page and multiple detail pages. This feature does not support all-in-one pages where "details" are anchor points within the same page.
• Markup on Summary or Category Pages: The markup should be on a summary or category page containing information about at least three entities, with links to detail pages. Detail page URLs must be included in the summary page's markup.
• Marking Up Items: Mark up all items on the summary or category page. For paginated categories, add an ItemList to each subsequent page. For infinite scroll, focus on marking up entities initially loaded in the viewport.

Google also provides several examples of how to implement this. For more details, check out the documentation here.