Currently rewatching Dragon Ball and I'm at the Tenshinhan Arc. Krillen defeats Chiaotzu in the tournament here so Goku nevers fights Chiaotzu and that got me to think if Goku has ever fought him which as far as I can find, I don't think he ever has in the original, Z, Super, Daima, GT, movies, or even anime filler. Not only that, but I think he is one of the only Z Fighters that Goku has never fought. And the other few are edge cases.
Yamcha in the Pilaf Saga, Roshi at the 21st Tournament, Krillen and Tenshinhan at the 22nd, Yajirobe in the King Piccolo Arc, Piccolo and Chi Chi at the 23rd, Vegeta in the Vegeta Arc, sparred with Gohan throughout the Android Saga, Android 17 and 18 much later on during the preparation for the Tournament of Power, Buu during the Buu Saga, sparred with Future Trunks in the Goku Black Arc, Goten and Trunks recently in the Super Manga on Beerus' planet, and Uub during the Peaceful World Arc and start of GT. Also, Broly in the Broly movie and Super Manga.
The only others I can think of are Videl, Bulla (both of those are definite edge cases), and Pan which I don't think we ever see him actual spar or fight her in GT. Maybe I'm wrong about the GT stuff for these three. Aside from them, I guess he hasn't fought Gamma 1 from the Super Hero movie either and he does seem like he will be a good guy going forward.
Am I missing anyone? Those last few aren't all that crazy, but considering Goku has fought the majority of the Z Fighters, it seems wild that he has never fought Chiaotzu which there would be no point in doing so at this point, but still wild that it never happened.