I personally prefer dogecoin and ethereum but these days ethereum also have network congestion and fee is really high so dogecoin is best right now.
Raiblocks is another coin that have no confirmation time and zero fee and I think it will be accepted in some casino soon because nobody wants to wait for hours to get confirmation and pay high fees just to move coins in and out of the casino.
What other coins you guys think can be viable option for crypto based casinos?