There's no macro which can cycle through targets without any additional mod filter etc. i,e:
/use [mod,shift,target=focus] SPELL [Tab buttom] = Shift Tab = Focus
/use SPELL [Tab buttom] = Tab = Main target
Or
/tar arena1 = Tab
/tar [mod:shift] arena2 = Shift Tab = arena target 2
/tar [mod:ctrl] arena3 = Ctrl Tab = arena target 3
This one can be a cycler. As closest you'll get to a cycling targeting macro.