Filters are a special kind of group. Once set up, they will filter the group they’re in and list all sheets that match the set criteria. For example, you can set up a filter that only lists sheets with a keyword “fantastic” or one that only lists sheets that have a comment block. If you place your filter deep within a nested group, say, six levels down, it will only show matching sheets within that nested group.
This article explains how to set a filter.