Well, I like card games and slots. The first one really ask from me a brain work, calculations and strategy.
Not all card games need strategy. Talk about blackjack you cant make that work by your brain. Now some people are going to talk about basic strategy and card counting. The point is that if you have seen live dealings then BJ is played with multiple decks to stop the players from counting cards. For online BJ games, forget about card counting, every deal is random.
Now poker is a game that is skill based. But slots again a completely EV- game which drains money very quickly.