Live poker is beatable, if you're better than the other players by enough to beat the house rake.
Video poker is beatable, if you find an appropriately favorable paytable, play nearly perfectly, and add in the cash back and promotions.
Craps: I'm becoming a believer in dice control. Many players whose opinion I respect are now playing craps profitably by learning to throw the dice in a controlled manner.
Even slots can be beaten sometimes. The concept of the 'banking' game surfaced several years ago, where some slot machines offer a bonus feature that builds value until it is won. By playing only machines that are in a favorable state, you can play slots profitably. The first machine of this type was called Piggy Bankin'. There are many more.
Roulette has been beaten by some players, by exploiting imperfect wheels that show a bias for certain numbers. There have also been several groups that developed successful computers that calculated where the ball would land based on the velocity of the ball and the wheel.
Sports betting can be beaten if you are skilled enough to detect when the spread doesn't accurately mirror the teams abilities.
Almost any card game on the casino floor has the potential to be beaten legally if the casino dealers are lax in their procedures.
There's a big world out there. Open your eyes.