I use treats for training as well as just an after ride bonding thing. For example, I use carrots for "carrot stretches" to get the horse to flex to each side as well as stretch down (carrot between the knees); it helps loosen him up prior to the ride.
After the ride to me is just tradition. A good poll rub (his special spot), a little bonding and one of his all time favorite treats, a peppermint or better yet, a Paddock Cake with the peppermint.
This time of year, if I can find a small enough bag, I also occasionally indulge with a hot bran mash. Applesauce, molasses, bran and carrots mixed in with hot water at tap temp. Recently I haven't been able to find less than a 50 lb bag of bran so I need to locate an alternative source.