Mystery writers used to love Tontines - because not only a great setup for murder, but if the murders was clever, it took a lot of deaths before you could narrow down your suspect list.
Not really good for itas idea but: I heard about (but am not sure) some modern life insurance pools are a sort of backdoor reverse tontine. Most people with life insurance cash them in before death, often at a hefty penalty. Well in some pools (and BillyTea I hope will correct me if I got this wrong) not all of that penalty is profit for the insurer. Some of it goes back into the fund and adds to the return for those who stay in. So you "win" by not cashing out while alive, but staying in until you die. Or at least the person collecting wins that way. I always wondered when hearing this, "are there really life policies with variable payouts like that?". Again BillyTea probably knows whether I misunderstood something or whether there are actual policies like this.