There's Touch (baseball) and Slam Dunk, which are good. Another baseball one is H2 which is by the same author as Touch but not as popular, but I still liked it. They're fairly old though, so it might be hard to find much of them. There's a newer series called Hajime no Ippo which is about boxing. What else...if you're into racing there's Initial D, and there's one about a judo girl called Yawara, though I haven't seen that yet so I don't know if it's good or not. The thing about sports anime series is that they tend to be really long, so it's quite hard to get all of the episodes. Good luck finding them!