Consider the one in my signature (777coin.com) too.

primedice.com, crypto-games.net are one of the oldest here. OneHash is another one I use.

Anyway, I hope you already found some good sites however there are some sites which will try to scam your money. Stay away from there. Normally they will give you free bets, you will win a good amount but before withdrawing the amount they will ask you to deposit x amount of BTC. Don't fall for it. It's completely scam.