What are some important/versatile subjects for a highschooler to reasonably self-study?

I am a rising Junior, I self-studied AP Calc BC, and AP Stats my Sophomore year.

Right now, I'm working on MVC and Linear Algebra.

After that I'll probably work on ODEs and maybe something else that I find interesting.

I want to major in Math or Astrophysics in college.

Does anyone have any recommendations for math subjects that would be useful or maybe interesting for me to learn about?

Thanks!