I would like to search for labels only, meaning pages, that have been marked with labels before. If I do a normal search, I get way too many hits.
You can search within Confluence for content which has been assigned keywords or labels. Use the prefix "labelText colon" in the search field.
We explain how this works in the Video #38 of our video tutorial series "Learn Atlassian Confluence".
You'll find additional options in the Confluence documentation of Atlassian starting on this page.