Major S4

Both anime are about baseball, both main characters are not intelligent however they are excellent at baseball and get stronger as the story progresses. However Major focuses more on the protagonist while diamond no ace goes more in depth into the entire team and the other teams. 

They both are about one guy taking a really bad baseball team and trying to take them to koshien. 

If you like sports anime capeta is very similar to major as it focus on one guy ( Capeta) and his will to become the best driver in the world. 

Both male leads goes to America and joins the Major League "to find their own baseball". 

Like Major, Moshidora is a sports anime, but not just baseball. It's about the dramas of life and being a human that struggles to deal with the challenges that life brings. Both animes have very touching moments that send a strong message: it was never about sport. It was about ourselves.