Vivaldi has a similar option: you can pick the tab position between top/bottom/left/right. I don't think it has the tab area reduction to show the icon only that edge has, so it does take extra screen scape.

And Opera before that also has the "place the tab bar at any side you want" option (Vivaldi's founder is one of Opera's founders who left after the Chinese takeover of Opera).

Sidebery for Firefox ís great.

https://addons.mozilla.org/en-US/firefox/addon/sidebery/