Here is a list of some of the important and frequently used MS Excel tools in offices:

1. Control C for copy
2. Control V for paste
3. Format painter and double click format painter to copy formatting of one cell to other cell or cells
4. Font size, font colour, fonts, bold, italic, underline
5. Text alignment
6. Wrap text to bring your text in one cell
7. Number formatting to use dates, percentages, etc.
8. Conditional formatting
9. Control T to convert range table into Excel table
10. Auto sum to quickly add numbers in a row or column
11. Sorting and filtering
12. Pivot tables to summarize and analyze data
13. Charts
14. Slicer and timeline to filter data
15. Print area to select the area you want to print
16. Gridlines to appear or disappear from worksheet
17. Excel formulas
18. Name manager to use defined names in Excel formulas
19. Power query to mash up and analyze data
20. New comment to insert comment box in cell
21. Freeze panes to freeze rows or columns
22. Macros to record macros
23. Shortcut keys to speed up the work in Excel
24. Hyperlinking to link various cells or worksheets
25. Flash fill to quickly split or merge data