Custom filter groups can be easily created to help shoppers customize the product listing on your collection pages:
Start by adding custom product tags to your products in the Shopify Admin:
In the Theme Editor under Collection, Collection page. In the Content section, choose Add tag grouping:
Add a Group name which will be displayed as the heading for the filter group. Followed by a list of tags for the group.
Groups and tags are dynamically displayed on collection pages. Tags within a group will only appear as filter options if the collection contains products that are tagged with the tag. For example, the group Color, will only show the filter option Terrazzo if the current collection has a product tagged with Terrazzo. If none of the tags in a group match the current collection, the entire group will be hidden.