The title should be self explanatory, but to clarify;
I would suggest adding in the functionality of Shift + 0 (numpad) considering how 0 (numpad) cycles target. The Shift + 0 (numpad) would cycle backwards, similar to how Shift + Tab does.

It is just extremely frustrating still that it is not there even though 0 (numpad) exist as a cycle target button. As a FFXI player who uses 0 (numpad) as my cycle target, I've grown used to using it.

I'm not even using Tab or Shift+Tab at all since I feel it is too awkward for my style. Currently having to rely on the mouse click to select my targets most of the time if I know I'm not able to cycle to it accurately.