Below is the list of 17 useful Excel Worksheet functions, please see below for details or check all the Excel functions here:

Closes ExcelAlt+F4
Inserts a new worksheetAlt+Shift+F1
Close selected workbook windowCtrl+F4
Restore the size of the selected windowCtrl+F5
Switch to next workbook windowCtrl+F6
Perform Move command when not maximized. Arrow keys to move and Enter or Esc key to cancelCtrl+F7
Perform Size command when not maximizedCtrl+F8
Minimize a workbook to an iconCtrl+F9
Maximize or restore workbook windowCtrl+F10
Create a new workbookCtrl+N
Open a spreadsheetCtrl+O
Save a spreadsheetCtrlS
Close a spreadsheetCtrl+W
Switches to the next workbook or the next tab in dialog boxCtrl+Tab
Switch between Worksheet, Zoom controls, Task pane and RibbonShift+F6
Insert a new worksheetShift+F11
Save the workbookShift+F12