Related Search is a SERP Feature that is displayed beneath the first page of search results. It presents a list of different but related search queries that might be of interest to a web user. Often, the related search is clicked by the web user in order to further refine their search.
The reason that this feature is located at the bottom of search engine results is that users will get to view it when they have failed to find what they’re looking for from the first 10 results. As such, the feature is considered useful in ensuring that more searches end in accurate findings for the web user.