A descending ladder of triceps dips and extended arm plank/knee taps. Your triceps make up 2/3 of your upper arm so it’s important to give them targeted attention. Remember, you’re still working your shoulders and triceps when in a plank so again, this is a superset style ladder.
A descending ladder of sit-ups and mountain climbers. Both moves challenge your abs in different ways: sit-ups in a time under tension manner, mountain climbers as dynamic ab work so again, a superset style ladder.