To minimise all windows apart from the one you are on. Select the window bar & shake it back and forth to minimise all other windows.
Ctrl + Tab: Cycle through open windows.
Ctrl + Shift + Tab: Cycle through windows & leave the menu open.
Ctrl Shift + N: Create a New folder.
Shift + Delete: Permanently delete, bypassing the Recycle Bin.
Ctrl + Shift + Esc: Immediately open the Task Manager.