I always found sports manga a very tricky genre. The reason being that it's difficult to visually present something as dynamic as a sport well. In most cases you also need some kind of affinity with the sport at hand. I've heard that both Haikyuu and Kuroko no Baskt are good series, but I never bothered reading them because neither volleyball nor basketball interest me.
I once read a series called Suzuka where athletics was the central sport and I liked it. However the sport on itself was nothing more than background. The real focus of the series was how talented athletes deal with real life issues that affect their sport achievement and vice-versa. The same author also created a short basketball series, but I only read that one because he was the author of Suzkua.
I also once read a football series called Giant Killing, but I just read it because I like football. It wasn't that particularly special.
Recently I read a series about waterpolo, but that was just because of the hilarious perverted gags. All the guys who joined the waterpolo club only did so because then they could eye goggle the girls of the club, which most of the time led to perverted antics.
Of course! For boxing, Ashita no Joe and Hajime no Ippo are best known for it. Try out Ashita no Joe first, which I personally like it way better than Hajime no Ippo.
As for martial arts, judo or wrestling can be included. Can't think of any atm.
Not really. Martial Arts is considered a separate genre from the sports genre. The reason is probably that many martial arts series tend to go over the top with the abilities of the martial artists, which are in most cases not even remotely realistic. Even series that try to appear somewhat normal, easily get seduced into trying to push it. Sports manga are almost always normal.
If you would search for Hajime no Ippo, most hosting sites would not tag it with the label martial arts, but with that of sports. It's probably the same thing with judo or wrestling.
Martial arts is something that seems to be specifically used for series where a large variety of fighting styles are used and/or where they are on superhuman levels. Something like HnI that only focuses on one specific thing and that as far as I know is normal, is a sports manga. So there is a subtle, but clear distinction between the two. No one is going to consider for example HSDK as being a sports manga, despite that both judo and boxing are prominent in it.