I want to read a manga where the main character is a teacher, but I don't want the typical shoujo of a teacher and student falling in love as the main story. other than GTO and Gokusen, are there any other mangas that revolves around a teacher?

You can try to check if Yasashii Sekai no Tsukurikata will go on that direction (it's quite soon to know now).
Also, Kodomo no Jikan deals with teacher stuff, but don't try it only if you're not fine with loli stuff.

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What I like in Trivial Pursuit style. Pick your category:

Um the only manga I read about a student and a teacher is this oneshot.

Sore wa, Nigai, Chocolate.

I guess the manga revolves around the girl's love problems most of the time. Also I guess it revolves around her affection towards the teacher and how the teacher tries to help her solve her problems. At the end they end up together. I don't find it like a typical shoujo so you can check it out if you want.

Also this one was recommended to me by some people but I never had time to read it.

Sugar Family

The reviews say it's sweet. I read a few pages of the first chapter and it seemed funny so it might be a comedy rather than all shoujo.

Hope I helped! ^-^

Dragon Zakura?

Seconding this. It's worth curbing any aversion you might have towards the art, because this is probably the only manga so far scanlated that's actually serious about studying, teaching and school-work in general.

second hammer session and dragon zakura.

Also
Sayonara Zetsubou-Sensei

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"you must prove more patient than a caterpillar, more willing to survive than a cockroach, and more stubborn than a leech - or you will definitely fail" - Counselor Rodriguez, the Star of Wisdom

Kamen Teacher (FUJISAWA Tohru)

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The only difference between saints and sinners is that every saint has a past while every sinner has a future. - Oscar Wilde

Jesus: like in hammer session, he is not really a teacher, he's a hitman. Full of action.

[m] Hammer Session!