Currently, Tags don't support a view to show all tags. However, we can use xmap to show all tags.
- Create a new menu called tag.(Joomla Menu)

- Add a menu item.(Joomla Menu Item)

- Create a new SiteMap, we can name it tag.(XMap)

- Add menu tag to the SiteMap tag, and sure tag only contains the menu tag.
- Open Options->Preferences

- Just copy HTML Sitemap url, then you can get a page with all tags.


