I think the problem is that below 10^-6 there's a pretty broad range of magnitudes that are effectively 'happens to n people every k years (if they try very hard)'. Which makes them rare but not impossible, which is annoying because you can't rule it out but you can't expect to easily reproduce it either.
That does tend to be the best way to think about those probabilities. For any probability you can make it happen If you try enough times or with enough people you can try to force it to happen. Below -6 is a pretty wide range of stuff you can just barely make happen if you have enough people, enough tries and enough time.
It's only once you get to the 'wouldn't happen to 10^10 people in a million years' that you get to the stuff that you can be fairly sure has never happened.
Matt Parker has quite a good video on it [1]. He settles on 10^-19 as something that you can be fairly sure has never happened (deliberately).
As for other stuff in the probability rows, maybe include a couple of well known paradoxes like the birthday paradox. And be clear what you're saying, things like getting dealt a royal flush depends a lot on the type of poker game.
