Chinese school group stereotypes?
Haha, that is an interesting question, I am going to try to list all the stereotypes I know.
First I will list some common ones regarding academic performance

学霸，very good student with hard working
学神，excellent student with little effort put in, also doing very well in nearly all other aspects you can think of, like sport clubs, video games and so on
学痞，academically excellent, little effort put in, difference with 学神 is, 学神 is more “仙” while 学痞 is more of an ordinary guy
学渣，not doing academically well because of no hard working
学酥，looking good when no exam is going on, will be found out to be 学渣 once exam comes, that is why they are called 酥，once being touched, they become “渣”
学屌，talented but not hard working students, performance varies with the effort they put in, but they do not care
学婊，always pretend to fail the tests but always end up with better grades than most of others, not a welcomed type

Then some regarding appearance

高富帅 or 高帅富，as the name suggests, tall, rich and handsome guy
白富美，again, as the name suggests, girl who is rich, beautiful and with fair skin
（男）屌丝，it is not a good word and is ONLY used for self reference, it means someone who is poor and ugly
女屌（丝），the female version of （男）屌丝，the rule is the same, ONLY self reference

And some others

宅男，guys who love comics and or video games, seldom appear publicly
宅女，female version of 宅男
逗逼/逗比，a funny guy, but use with care as it might sometimes be derogatory

I will keep this answer updated if I could think of any others.