Spatial navigation (Shift+arrow keys)

[LogicDaemon]

Initially Opera (on the Presto engine), and then eventually Vivaldi got a feature called Spatial Navigation.
https://help.vivaldi.com/desktop/shortcuts/spatial-navigation/

It allows holding Shift and using cursor keys (buttons with arrows) to move the focus to a nearest clickable element in that direction. It's much more convenient than Tab as it even allows navigating menus, but even without menus there are often tenths of links on a line (or a table row), and using Shift+Up and Shift+Down allows efficiently navigating them without going through the full row, as when using Tab.

Also the selected element is highlighted much more noticeably when using spatial navigation which allows seeing the selected 1x1px links for example.