I’ve been doing these sorts of interval workouts as well. I’m a big fan of

1) Sled Drag
2) Jump Rope
3) KB swing

If we have the warehouse, we do these for reps or distance without rest. Usually lasts about 5 minutes or so and is taxing. If we’re in the gym, I usually swap the drags out for something else–thrusters would probably work well. Mountain climbers are good in a pinch though maybe not quite hard enough once you get used to them. Box jumps are brutal. I bet trap bar deadlifts would work really well as they are suited to lots of reps…

Done for time with a little rest into built into the intervals, you get stretch it out and get a nice 15′ session out of something like this.

I find four cycles of Jump/Drag/Swing/Drag is lethal.