[Right-click] > Save Image As... (Mathematica Menu Item)

Save Image As saves the selected (or clicked upon) graphic in a file with the specified format.

File > Save (Mathematica Menu Item)

Save saves the current notebook.

File > Save Selection As (Mathematica Menu Item)

Save Selection As saves the selection in a file with the specified file format.

Format > Screen Environment (Mathematica Menu Item)

Screen Environment determines which style environment to use for onscreen display.

Edit > Select All (Mathematica Menu Item)

Select All selects all cells in the current notebook.

File > Send To... (Mathematica Menu Item)

Send To launches your email application to email a notebook (Windows only).

Show Breakpoints Window toggles the Breakpoints window on or off.

[Right-click] > Show Cell (Mathematica Menu Item)

Show Cell toggles between the expression and display forms of a cell.

Cell > Cell Tags > Show Cell Tags (Mathematica Menu Item)

Show Cell Tags toggles the display of cell tags in a notebook.

Show Debugger Tools Window toggles the display of the Debugger Tools window on or off.