The wierdest one I made for ttrpg was a nation built by orphans in an extrwmly poverty striken nation. Life is short and fast, you do what you can to help each other out and when someone dies they get they're name, date, and one sentence voted on by people that knew written in the book.

Their is no ownership, but if you take something you better have good reason or people won't help you out. If you want something done, do it or covince the people that can to do it.

You're expected to use contraceptives unless you know the orphanage can handle more kids. If you want to do something good with what little you've got helping to take care of poor kids like yourself at the orphanage is one most sure fire ways to do that. Holden up to raise just a kid or two out by yourself is no way to make a mark and who's gonna write your sentence some snot nosed kid isolated from the rest of the world by you? Why?

The moment that defined them as nation instead of just a community was when a nearby kingdom was preparing for a war path. They set out to create the equivalent of nuclear bomb, with many lives being lost trying to save themselves and each other. They finally made it, with many sentences being written of the kids that built a sun, and founded a nation. Their neighbors gave them a different sentence, because when they demonstrated it others had to turn they're heads from the blindly blaze, but the kids "did not look away" instead smoke glasses adored admired what their felllow orphans did with them.

Basically an anarchist society built on communal child rearing, and shared mythology of legacy of brief meaningful lives.