Next Tab (Recent) and Previous Tab (Recent) by Ctrl+Tab and Ctrl+Shift+Tab
Since all browsers use these two shortcuts, along with Ctrl+PgUp/Dn, to cycle tabs, both pairs working in the same way, thus wasting a pair of shortcuts that could be assigned to something else, I think Vivaldi could innovate here by assigning (or at least letting us assign) Ctrl+Tab to MRU Tabs (Next and Previous Recent Tabs), independently of the Tab Cycling "Cycle in Recently Used/Tab Order" (which I set to Tab Order).
I think it would still be intuitive as the two behaviors are the A and B of a same option. Maybe Ctrl+Tab and Ctrl+Shift+Tab could be, as an extra option, swapped with Ctrl+PgUp/Dn, but otherwise, I think Ctrl+PgUp/Dn should be kept for Tab Order cycling because it seems more fitting of the way it behaves now (my tabs are vertical, but still, I think it makes sense for anyone).
Totally missing the option to do that myself.
Big bump to this.
The right place for this is in the Feature Requests thread.