Although the following article mentions iOS (which I don't use), I learned some things about reopening tabs in MacOS Sierra. For me, it's useful stuff.
How to reopen tabs in Safari for iOS 10 and macOS SierraCool - I didn't know about the right-click on the plus sign in Safari - never thought of trying it. Very handy. I tend to get so many tabs open that I madly go about closing them at times - sometimes closing the ones I actually wanted to keep.
I knew about the menu functions - but the dropdown with the right click is far handier!