-Ideally something that pays 99-100% of collected funds to the winner and is verifiable with blockchain.
I doubt there will be lottery systems that will give about 99-100% of their collected funds.
Most of them are still keeping a large percentage for the house. And hard to track the actual collections.
But seems that there are few projects that are trying to integrate blockchain within their lottery system but not yet fully developed.
Maybe, later on, we will see a lottery business that we can easily verify their funds but giving 99-100%, very unlikely.