Speaking of terminals, I personally find that a combination of panes (i.e. arbitrarily nested horizontal + vertical splits) and tabs is really the best of both worlds.

Tile Tabs [0] was an extension that used to enable this kind of workflow for Firefox, but with the WebExtensions transition I thought it'd be no longer available, but it looks like I was wrong. There's a Tile Tabs WE extension [1] now, that attempts to replicate the same experience using windows, but it's not quite the same in terms of usability and space efficiency, and makes it mostly pointless if you have a decent tiled window manager that can accomplish the same layouts (which is what I have generally defaulted to ever since losing Tile Tabs).

This and vertical tabs are the kinds of features that I wish were built into the core of browsers because it needs a lot of UX attention to really shine. While I'm glad vertical tabs seems to be getting first-class treatment from WebExtensions, it's a shame that panes-based workflows appears to be getting shafted.

[0] https://addons.mozilla.org/en-US/firefox/addon/tile-tabs/

[1] https://addons.mozilla.org/en-US/firefox/addon/tile-tabs-we/