I got hooked up on one mobile games. First one is Pocket Champs where you compete against others in different maps. You have running, swimming, climbing, flying and you boost those skills the best you can.
Voidpet is not a bad Pokemon alternative. Although to me most mobile games including Voidpet is too repetitive. They require you to login and do some daily chores. it gets boring fast. Most mobile game systems are also designed to be grindy instead of strategic and challenging. Could just be the platform but man where are the good mobile designed games.