@IsseiTheOppaiMaster11 I got a few: Giant Killing (Football); Both H2 and Cross Game by Adachi Mitsuru (Baseball classics); BE BLUES ~Ao ni nare~ (Football); Major(Baseball classic); Captain Tsubasa(Football classic all the way back in to the stone age of manga, start with the beginning from when they are just at grade school.); Area no kishi (Football, English translation for it was dropped but seems got picked up again recently.)
Not on Mangadex : Whistle (Football classic, has full official translations, first few wave of manga got that officially translated); Shoot! (another Football classic all the way back to stone age)
Personal recommend that's neither Baseball nor Football: Haikyuu (It's a volleyball manga but god damn it is worth every single second reading it with it just ended not too long ago.); Hajime no Ippo (Boxing classic that is one of the longest running manga to date and its still running.); Yowamushi Pedal (Road cycling, it's worth it even if you only read/watch the first arc.); Slam Dunk(Basketball, when you ask name a sport manga classic to a 30 yr and above nerd this is probably it.)
I tried to recommend more grounded manga and avoided stuff like Prince of Tennis batshit crazy.