When i go to gym and see its full i start doing some random extra exercises, which you could do any where i guess.
box jumps - jump on to the box 1 leg and 2 leg, stacking crates or boxes on top of each other or use a table anything you can stand on that won't break.
grab any thing heavy (when i was at home i had these large tomato ketchup bottles about 5kg each) pistol squats.
rim jumps - try and jump high as you can to reach a certain point standing as well as running and maybe running one jump as well.
hurdle jumps - a good one i remember was told to me (get hurdles, or any obstacle you can jump over) and jump over it with one leg as well as 2 leg.
depth jumps as you said.
squats holding something heavy, heavy backpack, or a huge rock hold in front hugging it.
anything like this should be good i guess there's a whole list of it, from squat variations, etc.
hope this of some use.
