If you love the crime school type of genre or just want something REALLY SIMILAR to Extracurricular, I really recommend Bad Genius. Bad Genius is about a group of students who make money by cheating on test. It's also really good if you love suspense. Bad Genius also has a drama remake which was inspired by the movie.

I will say if you liked My Fuxxxxx Romance, you will be sucked into Friend Zone and invested. Friend Zone has the love triangles, but it is WAY MORE TWISTED! Just a warning that there's a lot of cheating and explicit content. It also has BL relationships if you were interested in that too. I will say, if you watch the first season, you need to watch the second season.

My Youth is similar to Remember My Boy of bulk of the storyline happening in the past and the life of high schoolers. If you like a simple straightforward drama, you would probably like My Youth.

Both of the dramas are quite different on the surface. Gakkou no Kaidan isn't a sci-fi while The Gifted is. What they do have in common is student empowerment and equality of students. How you shouldn't look down on others based on the background or how smart they are. Gakkou no Kaidan is about proper justice, while in The Gifted, the students want equality and try to express that everyone are just the same. The key similarity though is that they want to change and fix the corrupt education and school system. The Gifted is great if you're looking for student empowerment and super powers in one.