Red or Black

Some casinos play a version where you can also bet on whether the first card dealt in your next hand will be red or black. If it you choose correctly you win. But if the next card drawn is also the same colour card it is declared a tie. This side bet is good for the casino

Double Exposure

Some casinos play a version where both the dealers cards are dealt face up but blackjack is paid out at even money and the dealer wins all ties. This rule benefit's the casino.

Dealer may hit on "soft" 17.

Some casinos allow the dealer to take another card when their starting hand contains a 6 and an Ace. This rule benefit's the casino.

No splitting more than once.

Some casinos will not allow you to re-split a pair which has already been split. This rule benefit's the casino

No doubling down on soft hands.

Some casinos will not let you double down on any hand that contains an ace as one of the two cards. This rule benefit's the casino.

Double down on 10 and 11 only.

Some casinos will only let you double down when you hand has a value of 10 or 11. This rule benefit's the casino.