Safari Switch to Last Active Tab OS: Sierra

Safari: 10.0.3

It looks like the functionality to switch to the last active tab is not supported natively. Are there any extensions that can be used for this purpose? Furthermore, is there an extension that would give me a tab manager?

Note that I am unable to switch to a tab through the keyboard using the "Show all tabs" natively. The only solution that I found is through the use of Shortcat app.

I had to switch to using Opera for the time being for its awesome tab manager. With the addition of Vimium I can completely rely on the keyboard for all navigation (only partially supported with Safari through Vimari).

My only issue with Opera is that it isn't integrated with the default autocorrect/spellcheck engine, making life difficult for me.

Any suggestions for a tab manager/last active tab switch in Safari and/or a way to integrate Opera with the autocorrect engine is welcome (the latter, I think is dependent on this Chromium issue).
Have you checked out Recent Tab List? It's a Safari extension that allows you to manage open tabs and recently closed tabs in Safari.

You can reopen closed tabs quickly, as well as switch to open tabs. It also provides search functionality, so you can search for a tab. This is particularly useful if you have many tabs open across multiple windows.

Note: I am in no way affiliated with this extension.