This will be controversial- but I genuinely believe extracurriculars are important on your college application. *Especially for UC's or other extremely competitive universities*
Clubs: I recommend finding a club/ or a few that relate to your major or field of study. From there do your best to obtain an officer position and fully immerse yourself in the club.
Research: I personally got involved in research and LOVED it. My community college had plenty of research opportunities (you can typically find these through your honors program, an honors society, or specific professors). This looks amazing on college applications, post grad applications, and job applications. Get involved in something you are interested in.
Honor Societies: These are societies such as Phi Theta Kappa (PTK) or Psi Beta Honors Society. They are usually open to students with a certain GPA 3.25-3.5+ and provide you with amazing connections and opportunities. They typically cost about $50-100 for a lifetime membership and are beyond worth it.
Student Government: Each school has a student government that has many positions. This is a great way to have your voice heard and gain valuable experience. It typically is a time consuming commitment at about 10 hours/ week.
Work: Outside work is a great extracurricular. YES colleges look at your job and value it! Keep making that bank.
Volunteering: This is great for you as a student and as a person. All I have to say about this is if have the opportunity to volunteer- DO IT!