I just have barbell dumbbell or bodyweight options. I mostly deadlift at 5 x 5 x 70% of my 1rep max. Would your answer change if I went heavier on the DL?
Decrompression movements, basically.
I don't super set for heavy 5x5, I'm focussing on the next set. I'm not sure there's utility in super setting for the heavy compound stuff if it takes from the main exercise.
I've been just hitting something light to get some volume in when I'm in between actual heavy working sets lately.
Example: I was doing 5 or so sets of 6-8 reps of decently heavy squats recently. I would just hit a set of 5 pullups between each set I did while warming up and doing working sets. It was easy enough it didn't really impact my ability to hit my next working set, but by the end of the workout I had done 50 to 60 pullups without really even noticing.
You would do with with other stuff like dips or whatever too. Get that volume in if you're concerned with your working sets being significantly impacted by the fatigue of super setting.
Depends what you fancy.
At the moment I'm throwing in 10x high jumps or long jumps after a heavy 5x set.
It will diminish your actual lift (obviously, as another poster has stated) but depending on your goal it can be a welcome addition and a real killer if built in to a logical plan.