I think there are few of them exists and most of them are already here mentioned before. First of all I really love primedice and stake, they are owned by the same company so you can consider them as one place, primedice has been around for over 6 years now and that is a lot of time in crypto gambling space, nearly nobody runs for 6 years without ever having any problems with the customers, usually something happens that makes the casino or even exchange or even if its a forum like this have some issues with the customers about a scam.
Primedice never had anything like that. Stake is basically primedice but with more games so it gets a pass too. Nitrogensports is definitely the best casino out there, they were really old too if I am not wrong so the same thing I said to primedice applies to nitrogen as well.
You're completely right. You can rarely find a gambling website that's been running for years without having any complaints at all from customers regarding payments or anything like that and that's why Primedice is one of the best bitcoin gambling sites existing out there, being followed by its sister Stake. This two websites have managed to create a new type of gambling website with unique games and even though they don't have any slot games or live tables they are still two of the most popular crypto gambling platforms existing.