Stuck when it comes to extracurriculars

Sorry if this is in the wrong place or if this isn’t generally the kind of thing that should be posted here, but I need some advice regarding extracurriculars. I’m lacking in them, and don’t really know of any way to catch up.
I’m currently a junior in high school, and am very limited when it comes to transportation, which makes it difficult to do many clubs.

My current ec’s consist of

Track(varsity, 9, 10, 11)
Cross country (11)
Science National honor society (brand new to my school, so I haven’t had the chance to do much with this yet)

I also pet sit (for two people),and enjoy studying in my spare time, but I don’t really think that counts.

When I get a car, I will be able to get a job and do some volunteer work, but I’m not sure of when that will be.
I’m interested in studying physics or engineering in college, and was wondering if anyone could recommend some good ECs that would compliment that. My grades and test scores are very good, but after lurking around on here I’ve come to realize that for some of the more competitive schools, that won’t be enough.

Thanks in advance!

There are a number of different programming contests and activities online that you could do from home that would look good to colleges and would be valuable for a STEM major. If there are any local non-profits in your area you could offer to do web pages/spread sheets/databases as a volunteer activity that you could work on at home.

I’ll have to look into doing something like that! Thank you!