All platforms running Firefox: The Multiple Tab Handler extension adds a truckload of tab-related features to your right-click menu in Firefox. Select multiple tabs and refresh them, copy the URLs as HTML links or just a list, or move them into a new window with the Multiple Tab Handler. On a single tab, you can close all the tabs to the left or right, or close similar tabs (though it’s not clear what makes a tab “similar”—perhaps pages on the same web site.) While Firefox’s built-in tab group management is already pretty good, this extension really blows things out when you’re working with a bunch of tabs often. The Multiple Tab Handler extension is a free download and runs wherever Firefox does.