If you're looking for manga similar to Slam Dunk, you might like these titles. All recommendations are made by Anime-Planet users like you!
Tomomi is a high school dropout who was tragically responsible for crippling a beautiful girl he had just met; Kiyoharu is an ex track star whose bone cancer confined him to a wheelchair as a child; and Takahashi is newly handicapped due to an accident on his bike, stripping him as captain of the basketball team and his status as the alpha male of his gang of friends. Each of these young men shares something in common – their love for basketball. Though society may look down on them, these new friends will come to terms with themselves and their situations, and show their love of the game.
These mangas both portray basketball as intense, exciting, being written and drawn by the same mangaka, they share the same kind of comedy and art (though Real is by far superiorly drawn), They have very different feelings.
Slam Dunk is about a passionate, young delinquent who falls in love with basket and shares an amazing time with his high school mates. Real however follows a another basket ball delinquent who meets a handicap basketball player who moves like the wind.
If you like sports manga, these are probably the best, both of shounen and seinen.