Most school love have love triangles.... I'll give you some that have minor love triangles with minor characters:
Hadashi wo bara de fume
Kimi ni todoke
The death god dictates
The Gentlemen's Alliance Cross (Really good, but involves a love triangle. Sorry! It's my favorite school one though, had to recommend!)
Kimi Ni Todoke -
Kuronuma Sawako is completely misunderstood by her classmates. Her timid and sweet demeanor is often mistaken for malicious behavior. This is due to her resemblance to the ghost girl from "The Ring", which has led her peers to give her the nickname Sadako. Longing to make friends and live a normal life, she is naturally drawn to Kazehaya Shouta, the most popular guy in class, whose "100% refreshing" personality earns him great admiration from Sawako. So when Kazehaya starts talking to her, maybe there is hope for the friendships Sawako has always longed for. Maybe...there is even a little hope for some romance in her future.
Special A -
Hikari Hanazono has always been second to Kei Takishima. When they were six years old, their pro-wrestling loving fathers introduced them to each other. Assuming that she was the best in wrestling, young Hikari challenged Kei to a wrestling match only to be thoroughly defeated by him. Ever since that fateful incident, Hikari swore to beat Kei in school grades, sporting events - anything. To do this, she has enrolled in the same school as Kei since elementary. Now she attends Hakusenkan, an ultra elite school, that costs her carpenter father a lot of money. Hikari and Kei are the top two students in the school, with Kei holding firmly to that number one position. While Hikari considers Kei to be a rival and important friend, she is completely unaware that Kei loves her. The story primarily focuses on Hikari and her constant attempts to defeat her one and only rival, Kei, and how she finds love in their rivalry.
Akane Maniax -
Jouji Gouda is a new transfer student at Hakuryo High. He fell in love at first sight and boldly proposed to Akane Suzumiya, representative of his class, on his first day at the new school. Although Akane finds him very annoying, hot-blooded and simple-minded Jouji never gives up and would do anything to express his love towards Akane.
I hope this helps.
~Munto (Very awesome anime)
~Eden of the East
~Ef: A Tale of Memories
~Earl & Fairy
~Shakugan no Shana
~Tales of Vesperia
~Romeo x Juliet
~Kaze no Stigma
~Black Bird (Manga)
~ Ayashi no Ceres (Manga)
~Fushigi Yuugi Genbu Kaiden (Manga)
Ouran High School Host Club is by far my favorite
KissxSis if you like the dirty romance
School Rumble is a pretty good one.
Lovely Complex is decent.
Ah! My Goddess
Not exactly a school romance, but it is considered one of the best romance mangas.
It's called "Chobits"