Close all tabs in Safari except for one
Yes! You can do one of the following:


right-click on the tab you want to keep and select the Close Other Tabs option, or
make sure you’re on the tab you want and then use the optioncommandW keyboard shortcut (or, if you prefer using the mouse, hold down the option key and navigate to File > Close Other Tabs).


NOTE: - This closes all other tabs in the same window, not all tabs in all windows.

BONUS: You’ll find the above shortcuts are supported by most of the default macOS apps in macOS Mojave, including Finder, Terminal, etc. Some older macOS apps also support these, as do some 3rd party apps.