There are usually one or two balls floating around my weight room. Many people use them for a variety of exercises. If there's not one, you can take one in and use it during your workout and then return it when you're finished.

As for the step, I use a weight bench for the exercises that require a high step (step-ups, Bulgarian split squats). For the lower step, once again, there are usually one or two aerobics-type steps with risers in my weight room. Again, lifters use them for all kinds of things.

When I first started lifting, I would have felt very uncomfortable requesting this equipment from staff or bringing it into the weight area, but now that I've been working out in the free weight area for a while, I realize that nothing that I do is crazy or radical, and that lifters do all kinds of bizarre looking stuff when they're working out. I love watching other people lift because there are so many different combinations of lifts and body weight exercises that are out there.

The rule in the weight room at my gym seems to be, "Do whatever you want with the equipment you need, so long as you're not deliberately or rudely interfering with someone else. Put things back where you found them when you're done." I've found that most of the regular weight lifters at my gym are very nice and nonjudgemental.

If your gym doesn't have what you want or need, ask the staff to get it for you.

Agreed. For a higher step option I use a bench at one of the gyms I work out in (the other gym has platforms), and for a lower step option they have a lower step at both gyms. if they don't have a lower step you can always request to borrow one from another area of the gym (like the cardio area), the worst thing they can say is no. I'd be surprised if there are no swiss balls anywhere near the weight room, they have so many funcitons that it seems to me they've pretty much become standard equipment.