Here are some shortcuts I use and how I use them.
Alt+Tab: To switch to the last window I was on
Windows+E: Windows Explorer
Control 1,2,3,4: Switch between tabs on a browser
Control A: Select all. This is especially useful when I want to delete everything from a search bar but I’m only able to select part of the text. Just click Control A while you’re in the search bar and delete everything.
Control C, Control V: Copy, Paste
Control X: Cut. This is useful when you want to copy and delete at the same time.
Control Z: Undo. This is useful not only in Word documents in emails or other places where there is no clear “undo” button visible.