I found that setting a two minute timer and running up and down a stair case with high intensity once per day can resolve a whole host of seemingly unrelated issues.
I always run stairs when given an opportunity (big proponent of "incidental exercise"), so when I used to live in apartments I would deliberately rent a room in the highest available floor. It's shocking how much HIIT you can get out of running 20+ flights.
Same. I found that picking up a 28-kg kettlebell and climbing up a 20-storey building within 6 mins (switching up hands every couple of floors) is an awesome "functional" exercise.
Hits cardio, grip strength and unilateral stability stuff.