1. .xls – Microsoft Excel Spreadsheet
2. .xlsx – Microsoft Excel Open XML Spreadsheet
3. .xlsm – Microsoft Excel Macro-Enabled Workbook
4. .xltx – Microsoft Excel Template
5. .xltm – Microsoft Excel Macro-Enabled Template
6. .csv – Comma Separated Values
7. .txt – Text File
8. .ods – OpenDocument Spreadsheet
9. .slk – Symbolic Link
10. .xml – Extensible Markup Language
11. .dif – Data Interchange Format
12. .dbf – Database File
13. .prn – Printable File
14. .pxl – Pocket Excel
15. .gsheet – Google Sheets File
