Standard Views Toolbar

My Standard Views toolbar only has the ISO, top right and back views available. How can I get the front and left views to show on the toolbar?

You must have dragged those buttons off the toolbar while the “Toolbars…” dialog was open. (All toolbars are in edit mode whilst this dialog is open.)

So View (menu) > Toolbars… (dialog)
In the “Toolbars” panel, scroll down and select “Views” then click the “Reset” button.
Close the dialog.

Thanks. that corrected it. I will have to be more careful in the future.