You are talking about a decentralized gambling platform? It would be nice to see one. I am trying to imagine how will it be done? Who will hold the odd and etc. There must be a way though.
Yes, there is one actually
https://0xgame.io, It is a completely decentralized sports betting platform, I use it often could testify about it being totally decentralized, However it only supports ETH betting for now and I don't know if there could options available for other cryptocurrencies in the future, but I don't think that will be possible since it makes use of Ethereum smart contract functions.
Anyone else have checked this site to see if it's still online? I'm quite wary of opening links.