What extracurriculars should I do, if I'm interested in STEM specifically computer science?

When it comes to extracurriculars, while it could be beneficial to have STEM-related extracurriculars, in the end, what's really important is what you want to do. If any of those activities interest you, do them! I am planning to go into engineering, and while I have been involved in my school's robotics team for the past few years, I also am very involved in concert and marching band at my high school, only because I enjoy it. I've learned so much about working with people and being a leader through that too.

However, there are things that colleges look for in students who want to go into STEM fields. They want people who show good leadership qualities, which can come from any of the activities you listed if you have the dedication needed, but Student Council, FBLA, and NHS are all easy ones to show leadership in. Colleges do like to see activities related to what you want to go in to, but you shouldn't base your activities completely around that. Most computer science extracurriculars that I've heard about are ones that students pursue on their own, like participating in hackathons or publishing their own apps. Since there don't seem to be many STEM-related clubs or activities at your school, you could always start a computer science/technology club. It would take a lot of work, but it would show your passion for computer science, your motivation and dedication to it, and your leadership abilities.