I know edge at least supports vertical tabs? I don't like them though (I don't have enough horizontal screen space, plus it doesn't free up the top bar space). If I start to have many open tabs I start cutting them down anyway.
I'm not sure what you mean about not freeing the top bar though? The topmost thing I have is the back/forward/refresh/URL/extensions/menu bar. (file/edit/view/etc. hidden unless I press Alt, but that's not where tabs would be I don't think.)
edit: the latter (or Sidebery does do it but my previous solution didn't and this is now redundant, I suppose), I have:
#TabsToolbar {
visibility: collapse;
}
#sidebar-header {
display: none;
}