Most Helpful Guy
Baka & Test series.
DBZ good anime but does not fit the criteria
Cheeky Angel Tenshino konamaika
Detective Conan The best school anime in my opinion.
Sket dance (not about dance but about school)
and here is the link for you
Most Helpful Girl
Something similar with lots of female protagonists?
I think it would be "ojamajo doremi" lol.
W. I. T. C. H. too although it is not an anime.
If it is something about friendship?
Romeo no Aoi Sora is definitely my first pick. Then, HunterXHunter.
Here is a general list I posted in this question: