A smart filter option to filter list items and documents is being rolled out to SharePoint online tenants. Smart filters make it easy to find items with list or document library.
Working with Smart Filters
Open the smart filter pane by clicking on the filter icon at the top right of SharePoint list or library. For document libraries, 3 default filters options are available
Modified: Filter documents based on modified date range
People: Filter documents modified by one or more people
Type: Filter documents based on document type such as Word, Excel etc.
For lists smart filter option is available for column types date, person and choice.
To clear the filters click the filter icon at the top right of the smart filter pane. Filtered items could also be saved as Views.