In CarAI, I followed a tutorial to make a car followed a path made. There are more extra's coming, but it's in early development.
For Survival Shooter AI, I downloaded the finished product and added mutliple forms of knowledge for the enemies. They all walk between 2 points where the player is too far away. One just followed the player if he is in range, another one only follows him if the player is in range and is in the field of view for the enemie. The last one does that too, but also sends out a raycast to check if he really can see the player. The AI is made with a decision tree.
For hattrick I also downloaded a finished project and added an AI, also based on a decision tree, to make the hat move automatically towards the bombs you're supposed to catch and move away from the almost exploding bombs.
I remade pong wihtout any tutorials and added an AI system based on a decision tree to make the computer move the paddle towards the ball position, only if the ball is close enough. It's still beatable this way.