| xliff | XLIFF Document |
| xline | XLine Mind Map Document |
| xlk | Microsoft Excel XLS Backup |
| xll | Microsoft Excel Add-in |
| xlm | Microsoft Excel Macro Definition |
| xlr | Microsoft Works Spreadsheet |
| xls | Microsoft Excel Worksheet |
| xlsb | Microsoft Excel 2007 Document |
| xlshtml | Microsoft Excel HTML Spreadsheet |
| xlsl | Document Manager Locked Excel Document |
| xlsm | Microsoft Excel 2007 Document |
| xlsmhtml | Microsoft Excel HTML Spreadsheet |
| xlst | OnlyOffice Internal XLSX Document |
| xlsx | Microsoft Excel 2007 Document |
| xlt | Microsoft Excel Template |
| xlthtml | Microsoft Excel HTML Spreadsheet Template |
| xltm | Microsoft Excel 2007 Template |
| xltx | Microsoft Excel 2007 Template |
| xlv | Microsoft Excel VBA Module |
| xlw | Microsoft Excel Workbook Document |
| xlxml | Microsoft Excel XML Worksheet |
| xlz | Open Language Tools XLIFF Archive |
| xmap | XMind 2007/2008 Workbook |
| xmcd | Mathcad Worksheet Document |
| xmcdz | Mathcad Compressed Worksheet |
| xmct | Mathcad XML Worksheet Template |
| xmind | XMind Workbook |
| xml | Extensible Markup Language File |
| xmn | Sprintometer Document |
| xmt | Romulus 3D Modeler Data |
| xod | Silverlight XPS Document |
| xoi | eZediaMX Locked Presentation Document |
| xov | Rapidform XOV 3D Model |
| xpdl | XML Process Definition Language Document |
| xpf | Homestead Sitebuilder Document |