If you want the ability to save lists of Tabs, Firefox has https://addons.mozill...

If you want the ability to save lists of Tabs, Firefox has https://addons.mozilla.org/en-US/firefox/addon/tree-style-ta... which makes tabs appear in the sidebar, which makes managing even dozens of tabs simple.

Installing is one click - as simple as the chrome web store.

If you want the ability to unload tabs, firefox struggles with it. The best addon is https://addons.mozilla.org/en-US/firefox/addon/unload-tabs/ but it admits that it is buggy. Haven't tried it though.