If you're looking for manga similar to Shippu! Iron Leaguer OVA, you might like these titles.
A baseball team comprised of futuristic robot cats and a human make their way towards becoming a great team.
Karin Kiritani is a third-year student at Tokyo Metropolitan Hoshizakura High School who yearns to go to Koshien. She is a pitcher on the girls' baseball team, but is beaten by Mirei Hiiragi in the spring tournament. Under the guidance of her childhood friend Daimon Rai, Karin tries to improve her pitching form and grip on the ball, but will she be able to beat Mirei?
Entirely unknown nationwide is a high school student named Shino Ryuuji. At a national convention in his last year of junior high, he was allowed to go to a U-16 training camp as a Japanese representative candidate; that was to show a single part. In a friendly match against the U-17 Spain representative, Ryuuji was selected as one of the chosen to bathe in the severe baptism of the world!