Currently I am only in math team and science bowl, but am not in a leadership position for either. I used to be in debate but I quit this year because I wasn’t really enjoying it even though I did well. Right now my extracurriculars are looking pretty empty, so I would appreciate any advice on an EC to join, or whether it is possible to rejoin debate after missing one year. Also do you think it would it would be possible to do well in track if I prepare for it from now to when it starts? Kinda worried because I don’t feel like I can do much since I am already halfway through the school year as a Sophomore 
If you are struggling to find a EC that you enjoy have you thought about making your own?..founding a club looks great on a app and is something you’d enjoy too. It serves a purpose as leadership as well as outside involvement. It doesn’t have to be anything fancy, all you have to do is meet once or twice a month and that would do the trick.
I have the same problem as you, except I’m in less extracurriculars, and I’m a junior. I’ve been told that if you aren’t in many clubs or anything in school, spending a lot of time on a hobby or community service/volunteering outside of school looks good too. I spend a lot of time volunteering at my local animal shelter, for instance.
Hunting for ECs to look good for college and hunting for “leadership” positions is missing the point entirely! It won’t help your application so why not find ways to spend your time you think are valuable and meaningful to you?