I don't really understand how that is possible. If there's a casino managing the funds, no matter how reputable it is, it is still centralized. Perhaps you mean decentralized as the provably fair dice website that uses cryptocurrencies. Then the first one to check out is Primedice. Most of dice websites will be pretty much similar to it anyway, so this one should be enough. If you want some awesome animation, I suggest you to take a look at True Flip. The latter is not popular and is pretty new, but their animation is awesome (there is a girl-octopus in the science lab when the dice appear!). If you meant decentralized as trustless (dapps), you should consider smart contract casinos. The only dice smart contract casino I know of is Vdice, which used to have very high minimum bets, but things might've changed.